26 January, 2009

Miscarriage and the next pregnancy

Women who miscarry their first pregnancy are naturally distressed, but what reassurance about the next pregnancy is appropriate? If she conceives again and the pregnancy continues to viability, is she at increased obstetric risk, or not?

Battacharya et al (BJOG 2008;115:1623-9) followed up a large group of women who experienced a spontaneous early pregnancy loss and compared them to women whose first pregnancy reached viability and to women having their second pregnancy after a first normal outcome.

Unsurprisingly, the lowest risk was found in the group who had an initial uncomplicated pregnancy, followed by primigravidas, then those who had experienced a miscarriage. One miscarriage was associated with more obstetric complications, such as threatened miscarriage, pre-eclampsia, induced labour, instrumental delivery, preterm delivery and a low birth-weight infant, compared with those who had a successful pregnancy. Compared with primigravidas, they were more at risk of threatened miscarriage, induction, preterm labour and post-partum haemorrhage.

It is not clear whether this expectation of behaving like a “virtual primigravida” is related to the way the miscarriage was dealt with - by surgical evacuation, expectant management or medical evacuation. It is equally unclear whether waiting before trying for a replacement pregnancy will give a woman a better chance of a successful outcome. Steer suggests that an interval of 18 months may improve her chances (Editor's Choice BJOG Dec 2008).