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Introduction: Previous studies have shown an increased risk of obstetric complications in pregnancies after oocyte donation (OD). The present study includes all singletons born after OD over 10 years in Sweden.Material and Methods: This was a retrospective population-based cohort study. Data from all Swedish in vitro fertilization (IVF) clinics between 2003 and 2012 were collected. Data were cross-linked with the Swedish Medical Birth Registry. The study included 388 OD singletons, 26 696 IVF/ICSI singletons and 999 804 spontaneously conceived (SC) singletons. An adjusted odds ratio (aOR) was calculated with adjustment for relevant confounders.Results: Singleton OD pregnancies had a significantly increased risk of preeclampsia compared with IVF (aOR 3.05; 95% CI 2.23-4.16) and SC (aOR 2.84; 95% CI 2.10-3.84), and increased risk of postpartum hemorrhage (>1000 mL) compared with IVF (aOR 2.66; 95% CI 2.04-3.49) and SC (aOR 2.87; 95% CI 2.20-3.71), a higher risk of preterm birth (<37 weeks) compared with IVF (aOR 1.79; 95% CI 1.30-2.46) and SC (aOR 1.58; 95% CI 1.15-2.16) and a higher risk of low birthweight (<2500 g) compared with IVF (aOR 1.67; 95% CI 1.15-2.42) and SC (aOR 1.46; 95% CI 1.01-2.11). The rate of large-for-gestational age was significantly increased in singletons born after OD with frozen cycles than with fresh cycles (odds ratio 5.29, 95% CI 1.30-21.54).Conclusions: Singleton pregnancies conceived after OD are associated with increased maternal and perinatal risks compared with IVF/ICSI pregnancies using the woman's own oocytes and with SC. [ABSTRACT FROM AUTHOR]

BACKGROUND: The knowledge about air pollution effects on birth weight, prematurity, and small for gestational age (SGA) in low-exposure areas is insufficient. OBJECTIVES: The aim of this birth cohort study was to investigate whether low-level exposure to air pollution was associated with prematurity and fetal growth and whether there are sex-specific effects. Method: We combined high-quality registry information on 81,110 births with individually modeled exposure data at residence for nitrogen oxides (NOx) and proximity to roads with differing traffic density. The data were analyzed by logistic and linear regression with and without potential confounders. RESULTS: We observed an increased risk for babies being SGA when we compared highest and lowest NOx quartiles, adjusting for maternal age, smoking, sex, and year of birth. After additional adjustment for maternal country of origin and parity (which were highly intercorrelated), the increase was no longer statistically significant. However, in subgroup analyses when we compared highest and lowest NOx quartiles we still observed an increased risk for SGA for girls [odds ratio (OR) = 1.12; 95% confidence interval (CI), 1.01-1.24); we also observed increased risk among mothers who had not changed residency during pregnancy (OR = 1.09; 95% CI, 1.01-1.18). The confounders with the greatest impact on SGA were parity and country of origin. Concerning prematurity, the prevalence was lower in the three higher NOx exposure quartiles compared with the lowest category. CONCLUSION: For future studies on air pollution effects on birth outcomes, careful control of confounding is crucial. [ABSTRACT FROM AUTHOR]