Introduction
Preterm birth is one of the leading causes of neonatal morbidity, mortality, and severe long-term disability1. With the advance in infertility treatment, conception after in vitro fertilization (IVF) procedures has been recognized as a substantial increase in preterm delivery risk2. The increase in preterm delivery risk after IVF is found mainly due to the higher rate of multiple pregnancies, but also due to advanced maternal age, nulliparity, and co-morbidity2-6. However, some data demonstrate that adverse outcomes, preterm delivery included, occur in infertile women regardless of the mode of conception, IVF, or spontaneous, suggesting that infertility may be the underlying cause7.
While the body of studies exists on pregnancy rate and outcome in infertile women after IVF conception, there are scarce studies on pregnancy outcome of spontaneous conception after reproductive surgery8. The main reason exists in the opinion that reproductive surgery should only be performed as an initial part of infertility evaluation to increase implantation and pregnancy rates after IVF9. However, evidence shows that careful selection of patients for reproductive surgery enables couples to conceive spontaneously and yields high cumulative pregnancy rates and good outcomes8-10.
In the absence of obvious indication for IVF/ISCI procedure (like a male factor of infertility, bilateral tubal factor, or need for preimplantation genetic diagnostic), the usual approach to infertility treatment at our institution is, firstly, to restore fertility with reproductive surgery. Thus, every woman without any clear indication for IVF/ICSI undergo diagnostic or operative laparoscopy and, in the case of pathology found on transvaginal ultrasound, also a hysteroscopy. The usual overall pregnancy rate after reproductive surgery has been around 50%10. Women, who do not conceive spontaneously after reproductive surgery are advised to undergo IVF procedure.
Since the IVF/ICSI procedure has been supposed to be the known factor for preterm delivery4, we aimed to explore an association between the mode of conception, spontaneous or IVF/ICSI, and preterm delivery in a cohort of infertile women after reproductive surgery. We hypothesized that in infertile women after reproductive surgery, the mode of conception is not associated with preterm delivery risk. Also, the opinion is that any infertility treatment is associated with a higher risk of preterm delivery6. Thus, we aimed to explore the effect of reproductive surgery on preterm delivery as a treatment-related adverse outcome. We hypothesized that preterm delivery in infertile women is not a reproductive surgery treatment-related adverse outcome.