Scripties UMCG - Rijksuniversiteit Groningen
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The value of ante partum MR pelvimetry in vaginal breech delivery

(2012) Ruiter, A. (Anna-Marie)

in breech presentation the fetus’ buttocks are adjacent to the birth canal. During vaginal delivery, the breech fetus faces an increased risk of asphyxia, because the fetal is delivered last. The increased risks of neonatal morbidity and mortality in vaginal birth, whether they can be reduced and how these risks are proportionate to the maternal risks from caesarean delivery, has been an obstetric dilemma for decades. Although caesarean section for the breech presented fetus seems to lead to lower neonatal morbidity and mortality, there are substantial (long-term) maternal and neonatal risks involved for subsequent pregnancies due to the uterine scar. Therefore, breech delivery at term requires an evaluation of various determinants to decide the most suitable mode of delivery: trial of labor or elective caesarean section. If the woman opts for a trial of labor, in addition to adequate counseling one of the main determinants for this is the proportion of fetal weight to the maternal pelvis. For assessing the maternal pelvis, the antepartum MR pelvimetry can be used.
based on the study of van Loon et al.(1997), the antepartum MR pelvimetry is used in the at term breech protocol in the University Medical Center Groningen (UMCG) as a diagnostic tool to select the women who are able to succeed a vaginal breech delivery. However, since population and time has changed, the main purpose of this study is to find out if the antepartum MR pelvimetry is still useful in nulliparous women with a fetus in breech presentation. We investigated whether the emergency caesarean sections rate is lower due to the use of antepartum MR pelvimetry. Secondly, we analyzed whether there are confounding factors which increases the secondary emergency section rate. Ultimately, we examined if there is a significant difference in early neonatal outcome with respect to the secondary emergency caesarean section and the vaginal delivery.
Material and methods:
this study had a retrospective observational study design. From January 2001 to January 2012, nulliparous women who were pregnant of a singleton fetus in breech presentation at term were recruited in the UMCG and Martini hospital Groningen (MZH).The women in the UMCG (MR-group) underwent an antepartum MR pelvimetry after adequate counselling for a trial of labor. Women were included if they had an adequate pelvis according to the MR. In the MZH (non-MR group), no MR was performed. The main outcome measure was the emergency caesarean section rate.
there was no significant difference in the rate of secondary emergency caesarean sections between the MR group and the non-MR group. Moreover, induction of labor and a higher birth weight significantly increased the risk of a secondary emergency caesarean section. Last, early neonatal outcomes did not significantly differ between the neonates delivered vaginally versus the neonates delivered by secondary emergency caesarean section.
this study has shown that the antepartum MR pelvimetry has no distinctive diagnostic value to predict which women are able to give birth vaginally to a breech fetus. The assessment of a MR is time consuming, costly and only a few obstetricians are able to assess the MR. Seen this study and the mentioned disadvantages of MR, we would recommend to adjust the at term breech protocol of the UMCG. In conclusion, the abolition of the MR will be time and cost saving.

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