The aim of the study was to investigate maternal thyroid function in pregnancy by monitoring the circulating concentrations of thyroid stimulating hormone (TSH), free thyroxine (fT 4 ) and human chorionic gonadotrophin (hCG) in multifetal pregnancies before and after embryo reduction. We studied two groups of women: group 1 comprised singleton (n=12) and twin (n=12) pregnancies achieved after superovulation and in vitro fertilisation and embryo transfer (IVF-ET), and group 2 were multifetal pregnancies (n=39) undergoing selective fetal reduction to twin pregnancies. Blood samples were obtained initially at 10-12 weeks gestation (before fetal reduction) and then 4 and 8 weeks afterwards. Before fetal reduction, the circulating concentrations of fT 4 in multifetal pregnancies were significantly greater than those in singleton or twin pregnancies (singleton, mean 16·49 pmol/l (interquartile range14·09-18·13 pmol/l); twins, 15·84 (15·36-16·95 pmol/l); multifetal, 21·08 (16·64-26·29 pmol/l); P<0·005 for singleton and twins), and in a multiple regression analysis, fT 4 was significantly related to the number of fetuses (F=23·739, P=0·0001), but not to hCG. After fetal reduction to twins, the circulating concentrations of fT 4 in multifetal pregnancies decreased progressively towards those in control twin pregnancies, but remained significantly greater at both 4 (P=0·003) and 8 weeks (P=0·050). This pattern of change in the concentrations of fT 4 is similar to, but lags behind, that of hCG, which attains twin levels 4 weeks after fetal reduction. This may represent a delayed thyroid response to the decreasing concentrations of hCG, but the alternative is that the maternal thyroid function is controlled by a fetal factor in addition to hCG.

Although less common in the UK, postpartum haemorrhage (PPH)--defined as blood loss of 500 ml or more within the first 24 h of delivery--remains a significant cause of maternal death worldwide. Haemorrhage between 24 h and 6 weeks post partum is termed "delayed PPH". Common causes include retention of gestational products or endometritis. Bleeding can be sudden and profound, resulting in rapid cardiovascular collapse. A case of massive PPH 7 weeks after a caesarean section caused by a pseudoaneurysm of the uterine artery is reported. This case highlights diagnostic and therapeutic issues concerning this rare but potentially life-threatening condition and presents clinical features distinguishing it from other causes of PPH. Delay in diagnosis can result in repeated and catastrophic bleeding.

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