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Introduction: This retrospective study investigated the hypothesis that maternal hemoglobin (Hb) levels in twin pregnancy fall between the first and second trimesters and that higher falls are associated with higher gestational age at birth and higher birthweight (BW)., Material and Methods: The study population was defined as pregnant women with twin pregnancies delivering two live, phenotypically normal neonates, after 24 +0 weeks of gestation, between October 2009 and September 2021 at an inner London maternity unit. Maternal Hb and mean corpuscular volume (MCV), at ≤14 +0 weeks of gestation (Hb1) and again at 20 +0 -30 +0 weeks gestation (Hb2) were recorded from the Hospital's perinatal database. MCV was used as a possible indicator of iron deficiency anemia. The association of Hb drop, defined as [Hb1(adjusted for gestational age) - Hb2], and MCV values with gestational age at birth, BW of both twins and delivery of small for gestational age (SGA) neonates, defined as BW <10th percentile for gestation, was evaluated., Results: 923 pregnant women with twin pregnancies were included. Maternal Hb1 did not correlate with any outcomes measured. However, a lower Hb2 and a larger Hb drop was associated with a higher gestational age at birth (p < 0.001), a larger BW of twin 1 and 2 (p < 0.001 for both) and a reduction in the incidence of delivering one or two SGA neonates (p < 0.001 for both). MCV values did not correlate significantly with these outcomes., Conclusions: This study showed that in twin pregnancy, a larger maternal Hb drop from the first to the second trimester is associated with a higher gestational age at birth and a larger BW. This change may represent a larger plasma volume expansion., (© 2024 The Author(s). Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

Objective: To assess whether delivery mode and duration of labour in a first labour of spontaneous onset is associated with gestational length, delivery mode and neonatal outcome in the subsequent pregnancy., Study Design: Retrospective analysis of prospectively collected data., Setting: 15 Maternity units in North West London (1988-2000)., Population: 30 840 women with spontaneous onset of labour in pregnancy 1 and a subsequent birth reported in the same database., Methods: Assessment of outcomes by mode of delivery in pregnancy 1, restricting the analysis to the difference in the gestational length between pregnancy 1 and 2., Main Outcome Measures: Gestational length, mode of delivery and neonatal unit admission in pregnancy 2., Results: Caesarean section (CS) in the first or second stage of labour in pregnancy 1 was associated with pregnancy 2 being a median of 5 and 8 days shorter and a preterm birth rate of 6.0% and 10.1%, respectively, whereas following a normal or instrumental vaginal birth in pregnancy 1, the median duration was similar, with preterm delivery rates of 4.5% and 3.9%. In all, 56.2% of women with a CS in pregnancy 1 had a repeat CS and 12.5% of their babies were admitted to a neonatal unit, compared with 5.3% of women with vaginal birth. Longer labours were associated with shorter gestations in pregnancy 2., Conclusions: Compared with vaginal birth, an emergency CS in the first-term pregnancy is associated with a shorter gestational length, increased rate of repeat CS and increased risk of NNU admission in the next pregnancy., Tweetable Abstract: An emergency caesarean section in the first-term pregnancy affects the duration and outcome of the next pregnancy., (© 2021 John Wiley & Sons Ltd.)

Objective: To test the hypothesis that there is seasonal variation in the rates of gestational diabetes (GDM) diagnosed using a 2-hour oral glucose tolerance test., Design: Monthly assessment of the percentage of women screened from 1 April 2016 to the 31 December 2020 who were diagnosed as having gestational diabetes., Setting: London teaching hospital., Population: 28 128 women receiving antenatal care between 1 April 2016 and 31 December 2020., Methods: Retrospective study of prospectively collected data., Main Outcome Measures: Proportion of women screened diagnosed as having gestational diabetes., Results: The mean (SD) percentage of women diagnosed with GDM was 14.78 (2.24) in summer (June, July, August) compared with 11.23 (1.62) in winter (P < 0.001), 12.13 (1.94) in spring (P = 0.002) and 11.88 (2.67) in autumn (P = 0.003). There was a highly significant positive correlation of the percentage testing positive for GDM with the mean maximum monthly temperature (R 2  = 0.248, P < 0.001). There was a statistically significant 33.8% increase in the proportion of GDM diagnoses from June 2020 onwards, possibly related to a reduction in exercise secondary to the Covid-19 pandemic., Conclusions: There is a 23.3% higher rate of GDM diagnoses in the warmer summer months. There has been a 33.8% rise in GDM diagnoses associated with the Covid-19 pandemic., Tweetable Abstract: Rates of GDM are higher in summer and since the onset of the Covid-19 pandemic., (© 2021 John Wiley & Sons Ltd.)

Objective: To assess the relationship between race and spontaneous abortion, whether the relationship varies by risk factors, and the effect of spontaneous abortions on subsequent pregnancies., Methods: A retrospective study was undertaken using data collected in London, UK, between 1988 and 2000. Logistic regression evaluated histories of spontaneous abortion and associations with small-for-gestational-age and preterm births in black African, black Caribbean, and South Asian women relative to white European women. Interactions with risk factors were assessed., Results: Overall, 196 040 women were included. Compared with white Europeans, the odds of a previous spontaneous abortion were increased in black African (adjusted odds ratio [aOR] 1.20; 95% confidence interval [CI] 1.12-1.29) and black Caribbean women (aOR 1.31; 95% CI 1.21-1.41). The strength of the association with black African race increased with age (P=0.002), and the association with South Asian race increased with age and body mass index (P<0.001 for both). Spontaneous abortion was associated with preterm birth in all races, but was strongest in black African women (aOR 1.47; 95% CI 1.29-1.67)., Conclusion: The greater incidence of spontaneous abortion in black African and black Caribbean women should prompt further study of risk factors in relation to race. The interaction with age in black African and South Asian women could be important for counseling in relation to timing of pregnancy., (Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: To examine the effect of maternal characteristics, including advancing maternal age, body mass index (BMI), racial origin and development of gestational diabetes mellitus (GDM), on birthweight and the interactions between these factors., Design: Retrospective analysis of prospectively collected data., Setting: Fifteen maternity units in North West London, between 1988 and 2000., Population: A cohort of 130 549 pregnant women., Methods: Multivariate regression analysis., Outcome Measures: Birthweight z-scores in non-GDM and GDM groups within three main racial groups (white European, black and South Asian women)., Results: Babies born to women with GDM were heavier compared with those born to women with no GDM in all racial groups. In black women with GDM the birthweight z-scores were 0.805 higher, in South Asian women the scores were 0.618 higher and in white European women the scores were 0.437 higher, compared with the respective non-GDM group (P < 0.001 for both comparisons versus white European women), and these differences were much greater at high rather than at low maternal BMIs. Advancing maternal age, increasing BMI, highest diastolic blood pressure, Castair's index, racial group and presence of GDM or smoking were each, individually, significantly associated with birthweight z-scores (P < 0.001 for all variables). After adjusting for possible confounding factors, BMI was positively associated with birthweight z-scores within all racial groups (P < 0.001 for all), irrespective of glycaemic status, but its effect was much greater in women with GDM, particularly in those of non-White origin. After adjusting for possible confounding factors, advancing maternal age was only positively associated with birthweight in women of white European and South Asian racial origin who did not suffer from GDM (P < 0.001 for both)., Conclusion: Gestational diabetes mellitus strongly accentuates the effect of maternal BMI on birthweight, especially within non-white populations., (© 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2012 RCOG.)

Objective: To examine the individual association between advancing maternal age, body mass index (BMI) and racial origin with the development of gestational diabetes mellitus (GDM) and the interaction between these factors., Design: Retrospective study., Setting: Fifteen maternity units in northwest London between 1988 and 2000., Population: The study included 1688 women who developed GDM and 172,632 who did not. All women were nulliparous. BMI was calculated at first antenatal visit and maternal age and racial origin (White European, Black African, Black Caribbean or South Asian) were self-reported., Methods: Binary logistic regression analysis., Main Outcome Measures: Development of GDM within each racial group., Results: There was a strong positive association between advancing maternal age and increasing BMI, individually, and the development of GDM (P < 0.01 for both). Compared with White Europeans aged 20-24 years, the odds ratios for GDM development were significantly higher in women older than 30 years if they were White Europeans (P < 0.001), older than 25 years if they were Black Africans (P < 0.001) and older than 20 years if they were South Asians (P < 0.001). The odds ratios for GDM development were significantly higher in Black Africans and South Asians (P < 0.001 for both) irrespective of BMI, compared with White Europeans with normal BMI., Conclusion: Maternal age and BMI interact with racial group in relation to the prevalence of GDM. Both factors are important in the development of GDM, particularly so in Black African and South Asian women., (© 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2011 RCOG.)

Objectives: To investigate the effect of excluding cases with unrecorded best estimate of gestational age at birth on pregnancy outcome reporting and to determine the reasons for unrecorded gestational age data., Design: Prospective study., Setting: Fifteen maternity units in North West London., Population: 497,105 women who booked for antenatal care from 1988 to 1998., Method: Multiple logistic regression analysis., Main Outcome Measures: Preterm birth rate of, and the factors associated with, cases with unrecorded best estimate of gestational age at birth., Results: Of the 53,981 cases with an unrecorded best estimate of gestational age at birth, by using additional data, it was possible to compute a new best estimate of gestational age in 80%. In this latter group, the preterm birth rate was 42% (95% CI 41.5-42.6). The corrected, overall preterm birth rate in North West London (9.8%, 9.7-9.9) was higher than the original estimate (7.6%, 7.5-7.7), which included only cases with recorded data on gestational age at birth. The most significant factors associated with an unrecorded gestational age were no ultrasound scan (OR 49, P < 0.001), and preterm birth <31 weeks (OR 30, P < 0.001)., Conclusions: The incidence of preterm birth are likely to be under-reported in studies where only cases with readily available gestational age data are included. In routinely collected maternity data, human omission is an important contributing factor for an unrecorded best estimate of gestational age at birth. This is associated with the urgent transfer of babies to the neonatal intensive care unit.

Objective: To estimate the incidence of newborn respiratory distress syndrome (RDS) and transient tachypnea of the newborn (TTN) in relation to gestational age and planned cesarean delivery in white, South Asian, and black women., Methods: Included in this study were 442,596 white, South Asian, and black women who delivered single live infants at 28 of weeks gestation onwards between 1988 and 2000. Using multiple logistic regression, the gestation-specific patterns of RDS for all deliveries and RDS plus TTN for deliveries by planned cesarean delivery were analyzed by racial group. The predictors of RDS from 37 weeks of gestation onwards were determined., Results: More South Asians (28.2%, 95% confidence interval [CI] 27.8-28.6) and blacks (24.6%, 95% CI 24.0-25.1) delivered spontaneously before 39 weeks than whites (16.9%, 95% CI 16.8-17.1). Respiratory distress syndrome patterns by gestation differed significantly (P<.001). Compared with whites, the gestation-specific crude RDS rate was lower in South Asians up until 40 weeks and after adjusting for confounders; South Asians were most protected against RDS (odds ratio [OR] 0.6, 95% CI 0.5-0.9). The gestation-specific patterns of RDS plus TTN after planned cesarean delivery also differed significantly (P<.001) between racial groups. The lowest rate of TTN plus RDS was at 40 weeks for whites, but in South Asians and blacks, it was lowest at 38 weeks., Conclusion: The gestation-specific patterns of RDS differed significantly by racial group from 32 weeks of gestation onwards. Preterm black infants had a lower rate of RDS when compared with whites; also, South Asians had the lowest rate of transient tachypnea until 38 weeks and the lowest rate of RDS until 40 weeks of gestation. The advantages of waiting until 39 weeks to perform planned cesarean delivery for white women are not seen in South Asians or blacks.

Objectives: To determine if the risks of perinatal mortality and antepartum stillbirth associated with post term birth increase earlier during pregnancy in South Asian and black women than in white women, and to investigate differences in the factors associated with antepartum stillbirth between the racial groups., Design: Prospective study using logistic regression analysis., Setting: 15 maternity units in northwest London from 1988 to 2000., Participants: 197 061 nulliparous women self reported as white, South Asian, or black, who delivered a single baby weighing at least 500 g at 24-43 completed weeks' gestation., Main Outcome Measures: Gestation specific perinatal mortality, antepartum stillbirth rates, and independent factors for antepartum stillbirth by racial groups. Results The crude gestation specific perinatal mortality patterns for the three racial groups differed (P<0.001). The perinatal mortality rate among black women was lower than among white women before 32 weeks but was higher thereafter. Perinatal mortality was highest among South Asian women at all gestational ages and increased the fastest at term. After adjusting for the confounders of antepartum stillbirth (placental abruption, congenital abnormality, low birth weight, birth weight <10th centile, meconium passage, fever, maternal body mass index > or =30, and maternal age > or =30), the excess mortality among black women after 32 weeks was not significant. After adjusting for confounding, South Asian women still had a significantly higher risk of antepartum stillbirth (odds ratio 1.8, 95% confidence interval 1.2 to 2.7). Conclusions The risk of perinatal mortality increased earlier in gestation among South Asian women than among white women. The most important factor associated with antepartum stillbirth among white women was placental abruption, but among South Asian and black women it was birth weight below 2000 g.

Objective: To investigate the trend of neonatal resuscitation by intubation or mask ventilation over time and to assess its association with changes in prevalence of caesarean section and use of general anaesthesia in labour., Methods: All women booking pregnancy at any of 15 maternity units, analysed using logistic regression., Design: Prospective study., Setting: UK hospital-based maternity units (15 centres)., Population: A total of 221,322 first singleton births of babies weighing 200 g or more in the St Mary's Maternity Information System cohort, 1988-2000, covering the North West Thames area of London., Main Outcome Measures: Prevalence of intermittent positive-pressure ventilation (IPPV) (by intubation or mask) by calendar year., Results: Overall use of IPPV decreased markedly (two-sided P<0.01) over the course of the study, and this decrease was evident by all modes of delivery. Adjusted mean prevalence of intubated IPPV decreased from 0.51% (95% CI 0.44-0.58) in 1988 to 0.07% (95% CI 0.06-0.09) in 2000. There was a similar decrease in the prevalence of IPPV by mask. However, despite substantial increases in prevalence of caesarean sections and reductions in the use of general anaesthesia over the course of the study, adjusting for these variables made little difference to the temporal trends in intubation or use of mask ventilation., Conclusions: There has been a marked reduction in the prevalence of infants given resuscitation by positive-pressure ventilation that cannot be explained by changes in the prevalence of caesarean section or use of general anaesthesia in labour.

Birth in the human is particularly difficult compared with that in the other primates. Bipedalism has evolved over the past 6 or 7 million years, and has resulted in a small pelvis, adapted to the upright posture. In recent millennia, the increasing size of the fetal head at birth has made childbirth difficult. Haig has suggested that the mother and fetus do not have identical interests; the baby benefits from being large at birth, while it is easier for the mother to deliver a small baby. Many of the 500 000 maternal deaths per year around the world are due to obstructed labour, especially in Africa. Even in London, black African women have the highest caesarean section rates. Black African babies are on average smaller than white European babies, due mainly to earlier delivery. In a 13-year study of births in North West Thames, African babies were 2.5 times more likely to be born between 24 and 31 weeks inclusive than white European babies. Between 33 and 38 weeks of gestation, black African babies behaved in a more mature way, are more likely to pass meconium and have jaundice, but less likely to have respiratory problems leading to admission to the special care baby unit. Preterm black African babies have lower gestation-specific perinatal mortality than white European babies, while at term and beyond the reverse is true. Preterm birth may have evolved partly as a response to disproportion.

Objective: Failure of fetal growth during pregnancy, and preterm birth, are the major causes of stillbirth and early neonatal death. The objective of the study was to determine the association between maternal hemoglobin concentration during pregnancy and perinatal mortality., Study Design: The design was prospective, using data on 222,614 first singleton pregnancies in the St Mary's Maternity Information System database in the Northwest Thames region of London., Results: The association of perinatal mortality with maternal hemoglobin at first antenatal check was not statistically significant (P>.10), but a statistically significant (P<.001) U-shaped pattern was found with lowest recorded maternal hemoglobin concentration. Both early neonatal mortality and stillbirth rates were statistically significantly (P<.005) associated with lowest maternal hemoglobin concentration. The relationship of lowest hemoglobin with early neonatal mortality was largely mediated by the effect of preterm birth, and that between lowest hemoglobin and stillbirth by fetal growth restriction. The lowest perinatal mortality was associated with a lowest recorded maternal hemoglobin concentration of between 9-11 g/dL., Conclusion: There is an optimal range of lowest hemoglobin concentration in pregnancy, and on either side of this perinatal mortality is increased. The effect of lowest hemoglobin is largely mediated through associations with preterm birth and fetal growth restriction.

We investigated the possibility of preterm birth misclassification as a determinant of variation in its reported rates. Using a database of 497,105 deliveries from 17 hospitals, the best estimate of gestational age made at delivery and entered into the database at that time was recalculated from the menstrual dates and mid-trimester ultrasound scan. The recalculated completed weeks of gestation at delivery was compared with that made at birth. Calculation of estimated gestational age varied between hospitals due to inconsistencies in 'rounding' and 'truncating' the weeks of gestation at delivery. This resulted in preterm birth misclassification rates of up to 10.1%.

Previous research has produced conflicting results regarding the association of bacterial vaginosis (BV) and cervical intraepithelial neoplasia (CIN). These studies have been weakened in their conclusions mainly by failure to adequately control for the presence of sexually transmitted infections (STIs). One proposed mechanism suggesting that carcinogenic nitrosamines acting either independently or via human papilloma virus (HPV) has not been fully tested previously. We undertook a prospective, case-controlled, cross-sectional study where the presence of STIs, in particular human papillomavirus (HPV) which is known to be associated with the development of CIN, was controlled for. Women with BV were not found to have CIN more frequently than women with normal vaginal flora and the quantities of nitrosamines produced by women with BV did not differ significantly from women without BV. We thus found that BV is not associated with CIN.

Objective: To determine the changing patterns of HIV infection in women in three units in London., Subjects: Three hundred and fifty seven HIV seropositive women who have attended outpatient clinics between 1984 and 1992., Methods: A retrospective review of data obtained from a computerised database and supplemented by direct inspection of the notes., Results: The number of newly identified women with HIV has risen steadily over the period of study with a significant shift towards a heterosexual mode of transmission. This is a reflection of increasing numbers of women from Sub-Saharan Africa rather than a rise in the incidence of HIV in women born in the UK., Conclusions: The increase in women infected by HIV remains predominantly restricted to women in "high risk" groups. Although encouraging, our data should be interpreted with caution since it suffers from the inherent bias of selective testing. Safer sex education and epidemiological surveillance should continue despite the apparent low risk to women born in the UK.

A microcomputer system is described which stores data for perinatal audit and produces 'on-line' the statutory birth notification form and mother and baby discharge summary. The derivation of a minimum data-base and the methods used to obtain reliable data are outlined. The results of a trial of the production of the birth notification form for 195 deliveries are reported together with those of a further trial of 86 deliveries in which the system was used to produce both the notification form and the discharge summary. A study of the accuracy of the handwritten birth notification forms revealed a high error rate which was markedly reduced by the use of the microcomputer system. The system is now in routine use and further developments are outlined.