In Vitro Fertilization Linked With Increased Risk of Spontaneous Preterm Birth
HOBOKEN, NJ -- November 10, 2017 -- An analysis published in the Ultrasound in Obstetrics & Gynecology (UOG) found an approximate 80% increased risk of spontaneous preterm birth (both before 37 and 34 weeks) when women become pregnant via in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) than through spontaneous conception.
Preterm birth is more common in IVF compared with natural conception; however, the extent to which this it due to spontaneous labour or to iatrogenic indications has not been determined.
Paolo Cavoretto, MD, Obstetrics and Gynecology, IRCCS San Raffaele Hospital, Milan, Italy, and colleagues analysed data from 15 studies comprising 62,000 patients and about 3,800 preterm births events. All cases were singleton pregnancies.
The primary endpoint of spontaneous preterm birth <37 weeks was higher among the women who underwent IVF/ICSI (810 of 8,044; 10.1%) compared with women who conceived spontaneously (2,932 of 53,633; 5.5%).
Sensitivity analysis of studies matching for maternal age and parity maintained the significance (odds ratio [OR] = 1.63; 95% confidence interval [CI], 1.30-2.05).
Pooled crude analysis of secondary outcomes showed a significant increase in spontaneous birth <34 weeks among women who underwent IVF/ICSI (37 of 1,012; 3.6%) compared with spontaneous conception (24 of 1,107; 2.1%; OR = 1.78; 95% CI, 1.03-3.08).
“Placental development may play a key role in the pathogenesis of spontaneous preterm birth in IVF pregnancies,” the authors wrote. “We recommend ultrasound cervical screening in this high risk group in order to apply timely preventive strategies.”
“Future research reporting pregnancy outcomes should always emphasise etiological differentiation of preterm birth.”