Slow early β-hCG elevation is associated with increased risk for hypertensive pregnancy complications.

OBJECTIVE

To examine the association between rate of initial β-hCG rise following fresh in-vitro fertilization (IVF) cycles and long-term pregnancy complications.

METHODS

A cohort study including all patients undergoing fresh IVF cycles who had a single gestational sac on the first ultrasound and resulted in a singleton live birth. The elevation rate between the first β-hCG value taken at day 15 ± 1.4 after oocyte pick-up and second β-hCG value taken 2 ± 0.5 days later was assessed. A slow elevation was defined as doubling time above the 90th percentile of the study population.

RESULTS

Overall, 808 fresh IVF cycles qualified for inclusion in the study of whom 80 had a slow β-hCG elevation. There was no difference in baseline characteristics between the groups. The incidence of pregnancy induced hypertension was more than twice as high in the slow β-hCG elevation group compared to the normal β-hCG elevation group (14 % vs. 6 %, p 0.011). The adjusted risk ratio for this complication was 2.60 (95 % CI 1.26-5.33, p = 0.014) and remained significant after adjustment to maternal age, nulliparity and the first β-hCG value.

CONCLUSION

Patients with slow β-hCG elevation in the fifth gestational week were approximately at a 2.6-fold higher risk for pregnancy induced hypertension complications when compared to patients with a normal β-hCG elevation. The early detection of this previously unrecognized risk group could allow tighter follow-up during pregnancy, which could potentially reduce these complications.