2 oxytocin and nitroglycerin when performed by obstetricians who were experienced in this method [6, 7]. However, in an everyday clinical setting we noticed that many obstetricians with little or no experience in this method often failed in their attempts to remove the placenta. The primary aim of the present study was therefore to determine if oxytocin in combination with nitroglycerin is eﬀective in the management of retained placenta when performed by inexperienced obstetricians. Secondary aims were to examine hemodynamic eﬀects, blood loss, and side eﬀects following sublingual administration of nitroglycerin and to identify factors that could have a negative eﬀect on placental detachment. 2. Materials and Methods This was a prospective double-blind randomized controlled multicenter study that was carried out at ﬁve Swedish hospitals between October 2008 and July 2010. Two of the hospitals (hospitals A and B) were university hospitals with approximately 4100 and 6400 deliveries per year, respectively, while the three other hospitals were referral hospitals (hospi- tals C, D, and E) with 2100 to 3200 deliveries per year. At the two university hospitals some of the midwives were familiar with the use of nitroglycerin for management of retained placenta. None of the midwives at the three other hospitals or any of the obstetricians involved in the study had any clinical experience of the method. All participating obstetricians and midwives received written information about the study. Inclusion criteria were uncomplicated singleton pregnancy with spontaneous vertex delivery of a healthy child at term. Exclusion criteria were serious maternal disease, maternal age less than 18 years, blood loss more than 600 mL, uterine malformation, or suspected placental accreta. Thus, women with previous Cesarean section were not excluded from participating in the study. The study was approved by the medical ethics committees of the participating hospitals. All pregnant women who planned to give birth at any of the ﬁve hospitals received written as well as oral information about the study several weeks before expected delivery. According to the study protocol, if the placenta remained undelivered 30 minutes after child birth, a slow push of 10 IU (16.6 µg) oxytocin (Syntocinon, Novartis, Ta¨by, Sweden) was administered intravenously to promote uterine contractions and placental detachment. Five minutes after injection of oxytocin, controlled cord traction was performed once more to facilitate placental delivery. If the placenta remained undelivered 40 minutes after childbirth the women were asked to participate in the study. They were also informed about possible side eﬀects of nitroglycerin. In addition, intravenous administration of Ringer-acetate was instituted routinely as a prophylactic measure in case of postpartum hemorrhage and all the women were hemodynamically monitored. Randomization was carried out at a ratio of 1 : 1 by blocks of 4 (http://www.randomization.com/), and the allocation was performed by means of numbered opaque, sealed envelopes. A nurse who did not participate in the Obstetrics and Gynecology International remainder of the study handed out the study medication as needed. Following informed consent, the women were allocated to either of the two groups: (1) 1 mg of nitroglycerin tablets (two 0.5 mg tablets) Nitromex, Alpharma AB, Stockholm, Sweden) or (2) two placebo tablets. The tablets were administered sublingually approximately 50 minutes after childbirth. Neither the obstetrician nor the participating women were aware of the agent administered. Five minutes after administration of nitroglycerin or placebo tablets, gentle persistent cord traction was performed once more for a maximum duration of ﬁve minutes. The procedure was regarded as successful if the placenta was delivered in the delivery room without the need of operative manual removal under either regional (epidural or spinal) or general anesthesia. Maternal blood pressure and pulse rate were measured prior to administration of nitroglycerin or placebo tablets. These measurements were repeated ﬁve minutes as well as 15 minutes after administration of the tablets for assessment of possible hemodynamic eﬀects caused by nitroglycerin. In addition, total blood loss during the third stage of delivery was registered. Blood loss was assessed by weight and visual estimation, and in some cases also combined with measurement of collected blood poured into a measuring jar. The women also completed a questionnaire regarding possible side eﬀects of nitroglycerin. In addition, medical records were routinely checked in order to identify factors that could adversely aﬀect the outcome of the procedure. 2.1. Statistics. A sample size of 114 women (57 in each group) was calculated to yield a power of 90% at the 5% signiﬁcance level when assuming a success rate of 50% in the treatment group compared to 20% in the placebo group. Some withdrawals from the study were expected and therefore a sample size of 120 women was decided. Continuous variables between the treatment group and the placebo group were analyzed by using the Mann-Whitney U test, while the Chi-square test was used for analysis of dichotomous variables. For comparison between groups the Mantel-Haenszel Chi-square test was used for ordered cate- gorical variables and the Chi-square test was used for non- ordered categorical variables. The 95% conﬁdence interval was used for assessment of relative risk for dichotomous variables. Change from baseline variables within treatment groups was analyzed by using the Wilcoxon signed rank test. For categorical variables n (%) is presented and for continuous variables Mean, SD, median, min, and max are presented. Signiﬁcance tests were two-sided and conducted at 5% signiﬁcance level. 3. Results One hundred twenty women agreed to participate in the study. However, two women were excluded since only one tablet (0.5 mg) of nitroglycerin by mistake was administered. In addition, spontaneous placental detachment occurred in three women immediately before administration of tablets,