BACKGROUND While live birth is the principal clinical outcome following in vitro fertilization (IVF) treatment, the number of eggs retrieved following ovarian stimulation is often used as a surrogate outcome in clinical practice and research. The aim of this study was to explore the association between egg number and live birth following IVF treatment and identify the number of eggs that would optimize the IVF outcome. METHODS Anonymized data on all IVF cycles performed in the UK from April 1991 to June 2008 were obtained from the Human Fertilization and Embryology Authority (HFEA). We analysed data from 400 135 IVF cycles. A logistic model was fitted to predict live birth using fractional polynomials to handle the number of eggs as a continuous independent variable. The prediction model, which was validated on a separate HFEA data set, allowed the estimation of the probability of live birth for a given number of eggs, stratified by age group. We produced a nomogram to predict the live birth rate (LBR) following IVF based on the number of eggs and the age of the female. RESULTS The median number of eggs retrieved per cycle was 9 [inter-quartile range (IQR) 6–13]. The overall LBR was 21.3% per fresh IVF cycle. There was a strong association between the number of eggs and LBR; LBR rose with an increasing number of eggs up to ∼15, plateaued between 15 and 20 eggs and steadily declined beyond 20 eggs. During 2006–2007, the predicted LBR for women with 15 eggs retrieved in age groups 18–34, 35–37, 38–39 and 40 years and over was 40, 36, 27 and 16%, respectively. There was a steady increase in the LBR per egg retrieved over time since 1991. CONCLUSION The relationship between the number of eggs and live birth, across all female age groups, suggests that the number of eggs in IVF is a robust surrogate outcome for clinical success. The results showed a non-linear relationship between the number of eggs and LBR following IVF treatment. The number of eggs to maximize the LBR is ∼15.

Earlier reviews have suggested that IVF/ICSI pregnancies are associated with higher risks. However, there have been recent advances in the way IVF/ICSI is done, leading to some controversy as to whether IVF/ICSI singletons are associated with higher perinatal risks. The objective of this systematic review was to provide an up-to-date comparison of obstetric and perinatal outcomes of the singletons born after IVF/ICSI and compare them with those of spontaneous conceptions. Extensive searches were done by two authors. The protocol was agreed a priori. PRISMA guidance was followed. The data were extracted in 2 × 2 tables. Risk ratio and risk difference were calculated on pooled data using Rev Man 5.1. Quality assessment of studies was performed using Critical Appraisal Skills programme. Sensitivity analysis was performed when the heterogeneity was high (I² > 50%). There were 20 matched cohort studies and 10 unmatched cohort studies included in this review. IVF/ICSI singleton pregnancies were associated with a higher risk (95% confidence interval) of ante-partum haemorrhage (2.49, 2.30–2.69), congenital anomalies (1.67, 1.33–2.09), hypertensive disorders of pregnancy (1.49, 1.39–1.59), preterm rupture of membranes (1.16, 1.07–1.26), Caesarean section (1.56, 1.51–1.60), low birthweight (1.65, 1.56–1.75), perinatal mortality (1.87, 1.48–2.37), preterm delivery (1.54, 1.47–1.62), gestational diabetes (1.48, 1.33–1.66), induction of labour (1.18, 1.10–1.28) and small for gestational age (1.39, 1.27–1.53). Singletons pregnancies after IVF/ICSI are associated with higher risks of obstetric and perinatal complications when compared with spontaneous conception. Further research is needed to determine which aspect of assisted reproduction technology poses most risk and how this risk can be minimized.

Objectives To determine whether maternal obesity during pregnancy is associated with increased mortality from cardiovascular events in adult offspring. Design Record linkage cohort analysis. Setting Birth records from the Aberdeen Maternity and Neonatal databank linked to the General Register of Deaths, Scotland, and the Scottish Morbidity Record systems. Population 37 709 people with birth records from 1950 to present day. Main outcome measures Death and hospital admissions for cardiovascular events up to 1 January 2012 in offspring aged 34-61. Maternal body mass index (BMI) was calculated from height and weight measured at the first antenatal visit. The effect of maternal obesity on outcomes in offspring was tested with time to event analysis with Cox proportional hazard regression to compare outcomes in offspring of mothers in underweight, overweight, or obese categories of BMI compared with offspring of women with normal BMI. Results All cause mortality was increased in offspring of obese mothers (BMI >30) compared with mothers with normal BMI after adjustment for maternal age at delivery, socioeconomic status, sex of offspring, current age, birth weight, gestation at delivery, and gestation at measurement of BMI (hazard ratio 1.35, 95% confidence interval 1.17 to 1.55). In adjusted models, offspring of obese mothers also had an increased risk of hospital admission for a cardiovascular event (1.29, 1.06 to 1.57) compared with offspring of mothers with normal BMI. The offspring of overweight mothers also had a higher risk of adverse outcomes. Conclusions Maternal obesity is associated with an increased risk of premature death in adult offspring. As one in five women in the United Kingdom is obese at antenatal booking, strategies to optimise weight before pregnancy are urgently required.

The increasing prevalence of obesity in young women is a major public health concern. These trends have a major impact on pregnancy outcomes in these women, which have been documented by several researchers. In a population based cohort study, using routinely collected data, this paper examines the effect of increasing Body Mass Index (BMI) on pregnancy outcomes in nulliparous women delivering singleton babies.

Initial observational studies and a systematic review published 5 years ago have suggested that obstetric and perinatal outcomes are better in offspring conceived following frozen rather than fresh embryo transfers, with reduced risks of preterm birth, small for gestational age, low birth weight and pre-eclampsia. More recent primary studies are beginning to challenge some of these findings. We therefore conducted an updated systematic review and cumulative meta-analysis to examine if these results have remained consistent over time. The aim of this study was to perform a systematic review and cumulative meta-analysis (trend with time) of obstetric and perinatal complications in singleton pregnancies following the transfer of frozen thawed and fresh embryos generated through in-vitro fertilisation. Data Sources from Medline, EMBASE, Cochrane Central Register of Clinical Trials DARE and CINAHL (1984–2016) were searched using appropriate key words. Observational and randomised studies comparing obstetric and perinatal outcomes in singleton pregnancies conceived through IVF using either fresh or frozen thawed embryos. Two independent reviewers extracted data in 2 × 2 tables and assessed the methodological quality of the relevant studies using CASP scoring. Both aggregated as well as cumulative meta-analysis was done using STATA. Twenty-six studies met the inclusion criteria. Singleton babies conceived from frozen thawed embryos were at lower relative risk (RR) of preterm delivery (0.90; 95% CI 0.84–0.97) low birth weight (0.72; 95% CI 0.67–0.77) and small for gestational age (0.61; 95% CI 0.56–0.67) compared to those conceived from fresh embryo transfers, but faced an increased risk (RR) of hypertensive disorders of pregnancy (1.29; 95% CI 1.07–1.56) large for gestational age (1.54; 95% CI 1.48–1.61) and high birth weight (1.85; 95% CI 1.46–2.33). There was no difference in the risk of congenital anomalies and perinatal mortality between the two groups. The direction and magnitude of effect for these outcomes have remained virtually unchanged over time while the degree of precision has improved with the addition of data from newer studies. The results of this cumulative meta-analysis confirm that the decreased risks of small for gestational age, low birth weight and preterm delivery and increased risks of large for gestational age and high birth weight associated with pregnancies conceived from frozen embryos have been consistent in terms of direction and magnitude of effect over several years, with increasing precision around the point estimates. Replication in a number of different populations has provided external validity for the results, for outcomes of birth weight and preterm delivery. Meanwhile, caution should be exercised about embarking on a policy of electively freezing all embryos in IVF as there are increased risks for large for gestational age babies and hypertensive disorders of pregnancy. Therefore, elective freezing should ideally be undertaken in specific cases such as ovarian hyperstimulation syndrome, fertility preservation or in the context of randomised trials.