1. Introduction
The frequency of twin pregnancies is increasing worldwide due to
increased maternal age and the use of assisted reproductive techniques,
and adverse perinatal outcomes are higher in these pregnancies than in
single pregnancies (1-3). Managing this increase in the rate of twin
pregnancies is still a major problem. Also twin vaginal birth (VB)
presents a unique clinical challenge for obstetricians. Although there
is no consensus on the optimal method of birth in twin pregnancies, many
researchers suggest that if the first twin has a vertex presentation,
both twins are in the range of 1500–4000 g, and the second twin is not
significantly larger than the first, VB is recommended (4). Both the
American Congress of Obstetricians and Gynaecologists and the Society
for Maternal Fetal Medicine recommend VB of twin gestations with the
first twin in vertex presentation (5,6).
The reported cesarean rates of cesareans for the second twin range from
0.5% to 10% (7-9) and between 19.6 and 43.8% for both twins (10,11).
These large rate ranges show that cesarean sections are associated with
heterogeneous indications and some of these procedures are performed
when VB is possible.
Many studies in the literature compare the effects of VB and cesarean
birth (CB) on adverse pregnancy outcomes to clarify this issue. Although
some studies show a reduction in the development of adverse pregnancies
with CB (12,13), others report that adverse effects are not different
between the two forms of birth (4,14). The differences in study design
and the lack of quality randomized controlled trials are important
reasons for this obvious debate.
The aim of this study is to evaluate the safety of VB by comparing the
results of CB in twin pregnancies with the first twin in vertex
presentation.