November 17, 2017
2 min read

IVF increases spontaneous preterm birth risk by 80%

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Women who become pregnant through in vitro fertilization, or IVF, have an 80% higher risk for spontaneous preterm birth before both 37 and 34 weeks gestation, compared with those who conceived naturally, according to a study published in Ultrasound in Obstetrics and Gynecology.

“Preterm birth is more common among IVF as compared to natural conception,” Paolo Cavoretto, MD, from the gynecology and obstetrics department at IRCCS San Raffaele Hospital, Milan, and colleagues wrote. “However, the extent to which this is due to spontaneous labor or to iatrogenic indications has not been determined.”

Cavoretto and colleagues performed a meta-analysis of cohort studies to quantify the risk for spontaneous preterm birth in IVF pregnancies compared with naturally conceived pregnancies. The researchers identified 15 studies, including 61,677 births, that compared the risk for spontaneous preterm birth with conception from IVF or intracytoplasmic sperm injection (ICSI) and with natural conception. Of the 61,677 births, 8,044 were a result of IVF/ICSI.

Results showed that 10.1% of IVF/ICSI births were spontaneous preterm births, as were 5.5% of naturally conceived births. There was a significant increase in the rate of spontaneous preterm birth events among women who conceived through IVF/ICSI (OR = 1.75; 95% CI, 1.5–2.03), which remained after analyzing studies that matched for maternal age and parity (OR = 1.63; 95% CI, 1.3-2.05).

Spontaneous preterm birth events prior to 34 weeks gestation also significantly increased among those who conceived through IVF/ICSI (OR = 1.78; 95% CI, 1.03–3.08), with events occurring in 3.6% of IVF/ICSI births and 2.1% of naturally conceived births.

Compared with natural conceptions, IVF/ICSI conceptions had an approximately 80% increased risk for spontaneous preterm birth prior to both 37 and 34 weeks gestation.

“Placental development may play a key role in the pathogenesis of spontaneous preterm birth in IVF pregnancies. We recommend ultrasound cervical screening in this high-risk group in order to apply timely preventive strategies,” Cavoretto said in a press release. “Future research reporting pregnancy outcomes should always emphasize etiological differentiation of preterm birth.” – by Alaina Tedesco

Disclosures: The authors report no relevant financial disclosures.