Objective: To investigate the hypothesis that maternal haemoglobin (Hb) levels in twin pregnancy fall between the first and second trimesters, and that the size of the fall is associated with gestational age at birth and birthweight (BW). Design: Retrospective study. Setting: Inner London Maternity Unit. Population: Pregnant women with twin pregnancies delivering two live, phenotypically normal neonates, after 24 +0 weeks of gestation, between October 2009 and September 2021. Methods: Measurement of Hb, at ≤14 +0 weeks of gestation, (Hb1) and again at 20 +0-30 +0 weeks gestation (Hb2). Hb drop was defined as Hb1-Hb2. Small for gestational age was defined as BW <10th percentile for gestation. The association of Hb drop with gestational age at birth, BW, SGA and intertwin BW discrepancy of ˃25%, was evaluated. Main outcome Measures: Gestational age at birth , incidence of SGA neonates and/or intertwin BW discrepancy >25%. Results: 925 women with twin pregnancies. Maternal Hb1 did not correlate with gestational age or SGA or twins with BW discrepancy >25%. However, a larger Hb drop was associated with a higher gestational age at birth (p<0.001), a larger BW of both twin 1 and 2 (p<0.001) and a trend towards reduction in the incidence of delivering one or two SGA neonates (p=0.005 and p=0.003, respectively) or twins with BW discrepancy of >25% (p=0.005). Conclusions: The study has shown that a larger maternal Hb drop from the first to the second trimester is associated with a higher gestational age at birth, a larger BW and smaller BW discrepancy in twin pregnancies.

Objective To assess if delivery mode and duration of labour in a first labour of spontaneous onset is associated with gestational length, delivery mode 3and neonatal outcome in the subsequent pregnancy. Study Design Retrospective analysis of prospectively collected data. Setting 15 Maternity units in North West London (1988 to 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 spontaneous or instrumental birth in pregnancy 1 the median duration was similar, with preterm delivery rates of 4.5% and 3.9%. 56.2% of women with a CS in pregnancy 1 had a repeat CS and 12.5% of their babies were admitted to neonatal unit, compared with 5.3% of women with vaginal birth. Longer labours were associated with shorter gestations in pregnancy 2. Conclusions Compared to 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.

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 1st April 2016 to the 31st December 2020 who were diagnosed as having gestational diabetes Setting London Teaching Hospital Population 28,128 women receiving antenatal care between April 1st 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 (R2 = 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.