The incidence of intestinal obstruction in pregnancy ranges from 1 in 1500 to 1 in 66431 deliveries . Intestinal obstruction in pregnancy can be caused by many factors including congenital or postoperative adhesions, volvulus, intussusceptions, hernia and appendicitis . Sigmoid volvulus is the most common cause of bowel obstruction complicating pregnancy, accounting for up to 44 per cent of cases . Pregnancy itself is considered to be the precipitating factor for sigmoid volvulus. The occurrence of sigmoid volvulus in pregnancy is due to displacement, compression and partial obstruction of a redundant or abnormally elongated sigmoid colon by the gravid uterus . This could probably explain the increased incidence of sigmoid volvulus in the third trimester of pregnancy . Despite this higher propensity in the third trimester, there have been reports of this complication developing in the early pregnancy as well as the puerperium [2, 5, 16, 18].
To date, 84 cases of sigmoid volvulus have been reported occurring in the pregnancy and puerperium (Table 1). Lambert  reported 29 cases of sigmoid volvulus before 1931, followed by another 12 cases reported by Kohn et al  between 1931 and 1944. Subsequently, all the previously reported cases were reviewed by Harer et al  in 1958, who reported an additional 11 cases between 1994 and 1958. Later on, Lazaro et al  compiled another 13 cases occurring between 1558 and 1969. In this report, we have identified 19 more cases reported till 2009, and include another case managed recently at our institution.
The diagnosis of sigmoid volvulus is suspected when a pregnant female presents with a clinical triad of abdominal pain, distention, and absolute constipation. The average time from the onset of obstructive symptoms until presentation has been reported to be 48 hours . This is largely because pregnancy itself masks the clinical picture since abdominal pain, nausea, and leukocytosis can occur in an otherwise normal course of pregnancy . In our review of recent 20 cases, the mean delay between the onset of symptoms to presentation was 2 days, with a range from few hours to as many as 6 days, as seen in our case. Six patients presented more than 48 hours after the onset of symptoms. Harer et al  also noted similar delay in presentation in their review and concluded that such a delay in diagnosis and surgical intervention had a significant impact on the ultimate outcome of the mother and fetus.
The maternal and fetal outcome in sigmoid volvulus has been directly related to the degree of bowel ischemia and subsequent systemic sepsis. In our analysis of recent 20 cases, there were 4 (20 %) maternal and 8 (40 %) fetal deaths, including one ectopic pregnancy. It is important to note that all the maternal deaths occurred in the group of patients where delay in presentation and surgical intervention was more than 2 days. [2, 4, 14] Similarly, 5 fetal deaths were seen in patients who presented after 48 hours of onset of symptoms, as compared to 2 fetal deaths in patients presenting early in the course of the disease. This observation highlights the fact that high index of clinical suspicion is vital in cases of intestinal obstruction in pregnant patients. This facts needs to be emphasized amongst the general practitioners and community obstetricians primarily responsible for taking care of these patients.
Another important area of concern is the reluctance in the utilization of modern radiological diagnostic tools in pregnant patients. There have always been concerns about the radiation exposure of the fetus during pregnancy. Significant radiation exposure may lead to chromosomal mutations, neurologic abnormalities, mental retardation, and increased risk of childhood leukemia. Cumulating radiation dosage is the primary risk factor for adverse fetal effects, but fetal age at exposure is also important [22–24]. Exposure during the first week of gestation results in highest rates of fetal mortality. The next most sensitive time period is between 10 and 17 weeks of gestation, when central nervous system teratogenesis becomes an important consideration. After this period, the concern shifts from teratogenesis to the risk of childhood hematologic malignancy. It has been recommended that the cumulative radiation dose to the fetus during pregnancy should be less than 5–10 rads . In general, no single diagnostic study exceeds 5 rads of radiation exposure. As an example, the radiation dose to the fetus for a plain abdominal radiograph averages 0.1–0.3 rads, while a CT of the pelvis and abdomen yields up to 5 rads of fetal exposure . In any case, the health and life of the mother takes priority over the concerns for the fetus and judicious use of radiation may help make an early diagnosis with optimal outcome for both the mother and the fetus.
The management of intestinal obstruction and perforation in pregnant women is pretty much similar to that of non-pregnant women. The basis of therapy is early surgical intervention . Surgery should be performed via midline vertical laparotomy. In the third trimester, if sufficient intestinal exposure cannot be obtained due to enlarged uterus, a caesarean section must be carried out . The entire bowel should be examined for other areas of obstruction. Intestinal viability should be assessed cautiously and segmental resection with or without anastomosis is often necessary .