Obstetric outcome in 232 ovum donation pregnancies.

OBJECTIVE

To study the obstetric outcome of ovum donation pregnancies.

DESIGN

A retrospective analysis of 232 ovum donation pregnancies in the six years from 1988 to 1993.

SETTING

Infertility clinic in a private hospital.

PARTICIPANTS

All ovum donation recipients that achieved pregnancy in the clinic during the stated time period.

MAIN OUTCOME MEASURES

Percentages of live birth and miscarriages and ectopic pregnancies; number of sacs identified in the uterus at early (four weeks after transfer) and later scans; incidence of antepartum and postpartum haemorrhage; incidence of pregnancy-induced hypertension; incidence of preterm, low birthweight and small-for-gestational age babies; and incidence of operative deliveries.

RESULTS

Of 232 pregnancies, 151 babies were born (live birth rate of 20%); and 81 were lost (57 before eight weeks, 17 after eight weeks and seven ectopic pregnancies). In nine cases there were no intrauterine sacs at the early scan (two 'chemical pregnancies' and seven ectopic pregnancies). In 169 cases there was initially one intrauterine sac, ending with 102 singleton deliveries (60%); in 47 cases there were initially two intrauterine sacs, ending with 11 singleton deliveries (23%) and 32 twin deliveries (68%); in the seven cases where three sacs were identified initially, there were no singleton deliveries, three twin deliveries (one selective fetal reduction) and three triplet deliveries. Women with premature ovarian failures had a significantly higher pregnancy rate compared with those with functioning ovaries (P < 0.02). However, in the former group, the miscarriage rate was also significantly higher (P < 0.03) so that the number of term births was similar. The incidence of vaginal bleeding was 12% in the first trimester, 1.5% in the second trimester, and 2% in the third trimester. The incidence of postpartum haemorrhage was 12%. Thirty-two women had pregnancy-induced hypertension (23% of all deliveries). This occurred in 22/105 singletons (21%), 7/32 twins (22%) and in all three (100%) of the triplets. In the singleton group 13% of infants were preterm, 18% had a birthweight < 2.5 kg and 15% were < 3rd centile for birthweight at delivery (small-for-gestational age). Ovarian function was found to be the only factor that significantly influenced the incidence of small-for-gestational age babies (odds ratio 8.84; 95% confidence interval 1.1-70.0; P = 0.007). The overall operative delivery rate was 85% with the caesarean section rate being 69%.

CONCLUSIONS

Women who become pregnant following oocyte donation should be considered obstetrically as high risk, especially those with ovarian failure because of the increased incidence of small-for-gestational age infants in these pregnancies. They are also at higher risk of pregnancy-induced hypertension and postpartum haemorrhage.