Author(s): Hen Y Sela [[dagger]] 1 , Itamar Raz 2 , Uriel Elchalal 3
Caesarean section; delivery; diabetes mellitus; gestational diabetes mellitus; induction of labor; labor; macrosomia; pregnancy
Diabetes mellitus (DM) during pregnancy is classified as Type 1 (insulin dependent), Type 2 or gestational DM (GDM). GDM is defined as [1,2] :
"-glucose intolerance with onset or first recognition during pregnancy."
Most cases of diabetes diagnosed during pregnancy are GDM (90%), but rarely, it is due to formerly unrecognized pre-GDM. Complications during pregnancy diverge according to the classification of diabetes and the severity of the disease [3-6] . Pre-GDM and GDM increase the risks of complications for both the mother and fetus. The fact that the definition of GDM includes diverse patient populations may clarify some of the variation in the results of different studies with regards to pregnancy outcomes.
In this review, we aim to assess the data that have been accumulated regarding the management of labor and delivery of diabetic mothers in order to help to deliver optimal care during labor and delivery for these high-risk patients and, hopefully, to reduce the incidence of complications of both the mother and the fetus.
Increasing prevalence of diabetes in pregnancy
The exact incidence of GDM is unknown. The reported incidence in the literature is variable, and depends to a great extent on the characteristics of the population considered and the criteria used for the diagnosis. The risk for GDM is parallel to the risk for Type 2 DM within the general population [7-10] . Other risk factors include previous GDM, obesity, previous macrosomic newborn, familial history of DM, high parity and older age [8,9] . A Confidential Enquiry into Maternal and Child Health, published in London in 2005, which evaluated pregnancy in women with Type 1 and Type 2 DM during the years 2002-2003, it was reported that Type 1 DM accounted for 0.27% of all births, or one in every 364 births, and the prevalence of Type 2 DM accounted for 0.10% of all births, or one in every 955 births  .
The incidence of GDM reported in the USA ranges between 2 and 7% [7,11,12] . Worldwide prevalence is estimated to be between 2.8% (in Washington, DC, USA) and 22% (in Sardinia, Italy)  . The incidence rates of GDM are increasing worldwide [13,14] , reflecting the increased prevalence of Type 2 DM and obesity [15,16] .
Maternal & fetal complications related to labor & delivery
Many fetal complications, such as intrauterine fetal death (IUFD), neonatal hypoglycemia, congenital anomalies, macrosomia and increased prenatal mortality, are related to DM.
In pregnancies complicated by pre-GDM, the most important concerns during the third trimester are IUFD and both spontaneous preterm birth and early induction of labor owing to pregnancy complications that indicate premature delivery, such as preeclampsia (which is more prevalent in DM pregnant patients). The macrosomic newborn also carries an increased risk for both neonatal and maternal birth trauma [3,4,10,17-20] . In a recent study, it was found that women with pre-GDM were three-times more likely to have major maternal morbidity or...