**5.4. Preterm pairs**

There is limited existing evidence to determine the safest mode of delivery for extremely preterm twins. Therefore, it is important to consider the fetal presentation and weight when deciding the delivery mode, regardless gestational age.

A recently published meta-analysis showed no significant difference in neonatal death and severe brain injury by mode of delivery for cephalic/non-cephalic twins with a gestational age under 28 weeks [36]. This study found higher rates of maternal complications in growth-discordant twins.

## **5.5. Maternal conditions**

Higher rates of maternal morbidities are found in multiple gestations, compared to singletons. There is a higher risk of pre-eclampsia, diabetes and post-partum complications, as uterine atony and postpartum hemorrhage. Regardless, maternal conditions are rarely an indication of a cesarean section. An elective cesarean delivery can be performed after maternal request, after exposing the risks of the procedure, as longer maternal hospital stay, increased risk of the newborn going to the ICU due to respiratory problems and increased risks for subsequent pregnancies, as placenta previa and uterine rupture [37]. In those cases, the surgery should be planned to the appropriate gestational age, considering chorionicity and amnionicity.

**8. Associated risks: vaginal and cesarean delivery**

planned cesarean section or planned attempt vaginal delivery.

the first twin is in cephalic presentation [54].

cesarean delivery.

ders [58–60].

groups [61].

**10. Conclusion**

planned delivery [56, 57].

**9. Adverse neonatal outcome**

During the last few years, a lot of studies were performed trying to elucidate the question about the best delivery route for twins, according to the associated risks and benefits of

Time and Mode of Delivery in Twin Pregnancies http://dx.doi.org/10.5772/intechopen.80092 217

The twin birth study, showed that planned cesarean section was not superior to planned vaginal delivery regarding maternal risk or neonatal mortality or morbidity [53], and ever since some society guidelines suggest attempt to vaginal delivery to diamniotic twin pregnancies if

The concern about the risks includes the possibility of combined delivery, which involves an unplanned cesarean after attempt of vaginal delivery and is associated with higher second twin morbidity [14] and may be an increased risk of neonatal and/or maternal infection probably because the exposure to labor and rupture of membranes are higher than in a planned

Cesarean delivery can expose mothers to short-term risks such as endometritis, wound complications, surgical injuries, hemorrhage [55], although maternal outcomes past 3 month and long-term risks, including abnormal placentation, are similar both ways cesarean an vaginal

Newborns delivered by planned cesarean present a higher risk in developing allergic disor-

The twin birth study did not found statistically significant difference in morbidity and fetal or neonatal mortality between planned cesarean or planned vaginal delivery [14, 53], and a 2-year follow up after delivery found no difference in neurodevelopment and death in both

A retrospective study with 1070 twin pregnancies attempted trial of labor between 2003 and 2015 showed that in planned cesarean, the first twin has a lower blood pH and base excess than in vaginal delivery, but the study was unpowered for neonatal outcome assessment [13].

The time of delivery in twin pregnancies is around 38 weeks for dichorionic pairs, 36 weeks for monochorionic and 32 weeks for monoamniotic. When both fetuses are on cephalic presentation at delivery, the vaginal route is preferable regardless of weight. Being the first twin in non-cephalic presentation, cesarean section is the best choice. When the first twin is in cephalic presentation and the second non-cephalic, cesarean section is indicated if the fetus weight is less than 1,500g. However, vaginal delivery is possible if the fetus' weight is above
