High Order Multiple (HOM) pregnancies and IVF cycle number: is there an association?

Abstract

Objective: The avoidance of high order multiple (HOM) pregnancies is a significant concern in IVF cycles. This analysis was undertaken to determine factors placing women at risk for conceiving HOMs. We hypothesized that triplets may result from more aggressive treatment in couples who fail to conceive in early cycles, perhaps resulting from the transfer of more embryos. Design: Retrospective analysis of IVF cycles in which HOMs were conceived. Materials and Methdos: Our database identified 237 IVF cycles initiated in nulliparous women <41 years old between January 1995 and June 2002, resulting in ≥3 sacs on initial ultrasound. This group was contrasted with a comparison group of 8389 IVF cycles in nulliparas <41 who had 0–2 sacs on initial ultrasound, but were similar for all other parameters. Only non-donor oocytes cycles were included in the analysis. Results: The 237 HOM pregnancies identified included 215 triplet, 19 quadruplet and 3 quintuplet gestations. The largest group of HOMs (40.9%) were conceived in the first IVF cycle. Additionally, while a decrease in number of HOMs occurred with subsequent cycles, nearly 1/3 occurred in the 3rd and 4th cycles, and 21.3% of all HOMs occurred beyond the 3rd cycle in the face of an increasing number of embryos transferred and a normal follicular response. There was a slight increase in the number of embryos transferred with increasing cycle numbers. When compared to cycles that did not result in HOMs, there were a greater number of embryos transferred for each cycle number in the context of good ovarian response. The mean ages in the HOM and comparison groups were not significantly different (34.4 vs. 34.6). Previous cycle data was available for 122/140 patients who conceived HOMs in cycles 2–10 .In these women, there was an average increase of 1.3 embryos transferred in the cycle resulting in HOM as compared to the previous failed cycle. 9% of women were cancelled in the previous cycle, and 87% were not pregnant in the previous cycle. Of the 13% who had a pregnancy in the previous cycle, 7/16 (44%) transferred at least one additional embryo in the cycle resulting in a HOM. Tabled 1 Conclusions: In conclusion, the largest group of patients with HOMs conceived from their first IVF cycle. Additionally, over 20% of HOMs occurred beyond the 3rd cycle and up to the 10th cycle. Most of these occurred in the setting of increasing numbers of embryos transferred and a normal follicular response following previously failed cycles. Strategies to prevent HOMs include: limiting the total number of ET for all patients and avoiding the temptation to increase the # of ET in subsequent cycles in the absence of a pregnancy. Additionally, our data also suggest that no number of prior failed IVF cycles guarantees immunity to HOMs.