Search

Background: It is suggested that the skill of the physician performing the embryo transfer may influence the outcome of the procedure. In this study we investigated the effects of a change in embryo transfer technique on the variability in success rates among physicians., Methods: Retrospectively 4439 transfer cycles in which two different embryo transfer techniques were applied by seven physicians were studied. In the first 2210 cycles, transfers were performed using the 'clinical touch' method. In the following 2229 cycles, the so-called fixed distance technique was used., Results: With the clinical touch method pregnancy rates differed greatly among providers, whereas after the introduction of the fixed distance technique these differences disappeared. Furthermore, the overall clinical pregnancy rate increased from 33.6 to 40.4% per transfer. Using smoothing spline curves we failed to detect a sudden rise in pregnancy rates at the time the transfer method was changed., Conclusions: The introduction of the fixed distance technique greatly reduced the variation in pregnancy rates among physicians. The overall increase in pregnancy rates after the introduction is likely to be related to the change in technique although definite proof is difficult. Both observations are suggested to be attributable to the atraumatic character of the fixed distance technique.

A behavioural state transition is the time interval between two different behavioural states. In low-risk fetuses, the fetal heart rate pattern (FHRP) is the first variable to change in transitions from 1F to 2F ('non-REM-sleep' to 'REM-sleep') and the last variable to change in transitions from 2F to 1F. This is not the case in IUGR (intra-uterine growth retardation), and absence of a specific order in which behavioural variables are changing might be an indication for a (mild) disturbance of the fetal central nervous system (CNS). We investigated whether state transitions in twelve low risk term fetuses (39-41 weeks post menstrual age, PMA; control group) differ from those in twelve uncomplicated pregnancies > 41 weeks PMA (study group). All subjects underwent one behavioural study in which fetal heart rate pattern, eye and body movements were recorded simultaneously. We recorded 23 transitions from 1F to 2F and 20 from 2F to 1F. Median (range) duration for transitions from 1F to 2F was 85 (10-180) s in the study group, and 60 (10-180) s in the control group. Transitions from 2F to 1F lasted 80 (10-140) and 60 (30-100) s, respectively. In both groups, the FHRP was the first variable to change in transitions from 1F to 2F, however, in transitions from 2F to 1F, no specific order in change of variables could be demonstrated. We conclude that the study of transitions does not distinguish between the term and after term fetuses under optimal conditions. Whether or not the analysis of state transitions can be used to distinguish 'normal' from 'abnormal' fetuses and detect the fetus at risk after term awaits further study.

The metabolism and distribution of a single oral dose of 25 mumol 14C-labelled 3,3',4,4'-tetrachlorobiphenyl (14C-TCB) were investigated in pregnant female Wistar rats and their fetuses. TCB was administered on day 13 of gestation and the elimination was followed for 7 days. Non-pregnant rats were treated similarly for comparison. Fecal elimination of 14C-TCB derived radioactivity was significantly lower in pregnant rats than in non-pregnant rats. The major metabolite found in adult liver and plasma, placental tissue, whole fetuses and fetal plasma was 3,3',4',5-tetrachloro-4-biphenylol (4-OH-TCB). Tissue levels (liver, abdominal fat, skin, skeletal muscle, kidney and plasma) of 14C-TCB-derived radioactivity declined by 65-85% over a 7-day period following administration in the adult animals. However, 14C-TCB-derived radioactivity accumulated more than 100-fold in the fetuses over the same time period, and GC/MS analysis revealed that the fetal accumulation in radioactivity was due primarily to 4-OH-TCB, and not the parent compound. On day 20 of gestation, concentrations of 4-OH-TCB were 14 times greater in fetal plasma than maternal plasma. Treatment with 14C-TCB significantly reduced plasma thyroxine levels by at least 28% up to 7 days after administration in non-pregnant animals and up to 4 days after administration in pregnant rats (31% decrease). By 7 days after administration plasma thyroxine levels had returned to control levels in the TCB-treated pregnant rats. However, fetal plasma thyroxine levels were significantly decreased by 35% in fetuses from 14C-TCB-treated dams 7 days after TCB administration. Hepatic microsomal ethoxyresorufin-O-deethylase (EROD) activity was significantly induced in TCB-treated dams relative to controls at 4 and 7 days after administration, while no EROD activity was detected in hepatic microsomes from control or TCB treated fetal rats at day 20 of gestation. These data suggest that hydroxylated metabolites of polychlorinated biphenyls may play a role in the development toxicity of these compounds.

The development of fetal behaviour and of fetal behavioural states (FBS) has been well defined in preterm and term fetuses. However, FBS have not yet been studied after term, although this is a potentially very dangerous period and clinical management is controversial. We investigated fetal behaviour in normal pregnancies after 41 weeks of gestation (287 days, menstrual age, GA) as compared to control term fetuses. Furthermore, we wanted to see if the findings might have consequences for clinical management. Twelve healthy women with GA between 289 and 298 days participated. All pregnancies were reliably dated and at the time of the study, there was a normal amount of fluid. Twelve healthy women with GA 273-287 days served as controls. All subjects underwent a behavioural study using cardiotocography to record the heart rate (CTG), and two ultrasound scanners to observe body and eye movements, as described previously. All fetuses in both groups clearly exhibited FBS 1F-4F which fitted the definitions of Nijhuis et al. The median percentage of FBS 3F and 4F ('awake states') increased significantly from 6% in the term group to 21.5% in the fetuses after 41 weeks (P = 0.014). FBS 1F ('quiet sleep') and 2F ('active sleep') decreased from 92 to 78% (P = 0.014), mainly at the expense of FBS 2F which decreased from 78 to 58% (P = 0.002). This indicates increasing wakefulness in utero. The fetal heart rate patterns (FHRP) associated with FBS 3F and 4F were impressive. For example, in FBS 4F, the FHRP showed large amplitude, prolonged accelerations which fused into a sustained tachycardia with only short periods of return to the baseline, resembling tachycardia with decelerations. We conclude that in normal pregnancies after 41 weeks, the development of the fetal central nervous system continues, resulting in an increasing percentage of 'fetal wakefulness'. The CTG-patterns that result from these behaviours can easily mimic fetal distress and one should be aware of this phenomenon. Whether behavioural studies can be used to distinguish 'normal' from 'abnormal' fetuses after term awaits further study.

This study examined the effects of supplementing patients with cystic fibrosis daily for 4 weeks with 1,500 mg borage oil, containing 330 mg gamma-linolenic acid, on the fatty acid composition of serum phospholipids (PL) and cholesteryl esters (CE). Vital capacity and forced expiratory volume in 1 s were also measured before and after treatment. In serum PL the content of arachidonic acid (AA) increased and that of palmitic acid decreased significantly after borage oil administration. In serum CE dihomogamma-linolenic acid increased whereas docosahexaenoic acid decreased significantly. In this lipid class, AA and the sum of AA plus its precursor, dihomogamma-linolenic acid, increased significantly with the dose fed. A positive correlation was found between change in vital capacity and change in linoleic acid content of serum CE and AA content of serum PL.