Thank you for this interesting question. uterine contractility (activity) can be one of the major causes of placenta abruption.  what can cause uterine activity to increase is the level of oxytocin in the circulation. Dehydration (caused by fasting) is a major cause of oxytocin release which will then increase the uterine activity.

This is my personal explanation depend on personal analysis of the events

Lakea et al (1997) found in a British cohort study that overweight and obesity in early adulthood appear to increase the risk of menstrual problems, hypertension in pregnancy increasing the risk of abruptio placentae. In a large cohort of singleton pregnancies Aliva et al. (2010) found that the risk of preeclampsia and eclampsia increased significantly with increasing BMI and decreasing age. Extremely obese teenagers were almost four times as likely to develop preeclampsia and eclampsia compared with nonobese women and teenagers were most at risk because of the combined effects of young age and obesity. In estimating risk factors for preeclampsia Baker and Haeri (2012) confirmed that maternal obesity and excessive gestational weight gain place the gravid teen at increased risk for preeclampsia. They suggested that the modifiable nature of these risk factors permits the possibility of intervention and prevention. 

A recent study study of the interrelationship between gestational weight gain, pre-pregnancy body mass index, race/ethnicity with hypertensive disorders during pregnancy showed that although there are some ethnic/racial variations, pregnant women who exceeded gestational weight gain recommendations are at increased risk of hypertensive disorders and risk of abruptio placentae (Masho et al 2016).

It is important to look into other risk factors that were linked to abruptioplacenta. Those documented in the literature, you might be missing another risk factor rather than fasting. Such as age group, BMI, stress. Ramadan is associated with various cultural practices that can contribute to abruptio placenta rather than fasting. 

It would be interesting if you would describe the habits of Ramadan that you see in detail in your area.   In Israel, we see that Arabs observing Ramadan fast during the day and heavily binge on sugar  during the evening and night.    If that is the case where you are also, the question could be equally accurately phrased: "Can bingeing on sugar containing foods be associated with placental abruption?"

     Another thing that I would appreciate knowing is actual numbers.   You state that placental abruption dramatically increased.   We all know that placental abruption is very rare,   so having twice the amount  STILL amounts to it being is very rare, and the words  'dramatically increase'   could easily be explained by random events.  

I think fasting Ramadan has nothing to do with placental abruption. Our observation of fasting ladies in Ramadan did not showed any rise in incidence of abruption.

In general, is it wise to encourage pregnant ladies to fast

Actually, we need more research in this area, but  I am agree with Dr.Lina.Recently we are observing many patients to come with uterine contractions due to dehydration. After i.v.fluids they became quite happy. In my clinic I use patient information leaflets from http://www.babycentre.co.uk/a1028954/fasting-in-pregnancy translated into Arabic for my patients. Good articles about fasting and pregnancy outcomes

 Iran J Pediatr. 2010 Jun; 20(2): 181–186.

PMCID: PMC3446023

The Effect of Ramadan Fasting on Outcome of Pregnancy

Vahid Ziaee, MD,1,2,3,* Zarintaj Kihanidoost, MD,2 Masoud Younesian, MD,4 Mohammad-Bagher Akhavirad, MD,5 Farzad Bateni, MD,1 Zahra Kazemianfar, MD,1 and Sedigheh Hantoushzadeh, MD6

J Obstet Gynaecol Res. 2008 Aug;34(4):494-8. doi: 10.1111/j.1447-0756.2008.00814.x.

Effect of fasting during Ramadan on fetal development and maternal health.

Dikensoy E1, Balat O, Cebesoy B, Ozkur A, Cicek H, Can G.

Thank You.

No

I agree to see other factors relating to abruptio placenta. Some references showed that there is no direct relationship between nutrition and birthweight. Placenta perfusion has important role to maintain fetal wellbeing, including abruptio placenta

no relation between abruption placenta and fasting Ramadan, most references showed that the hypertension disorder during pregnancy and preeclampsia direct relation between placenta perfusion and abruption placenta  

there's a relationship between fasting and induction of labor.It was "the natural way" to induce labor : dehydration- oxytocin release-contraction. Abnormal uterine activity can cause placental abruption..

Abruptio placentae, is the premature separation of the normally implanted placenta from the uterine wall before labor and delivery of the newborn. Bleeding occurs between the uterine wall and the placenta.no relationship between fasting and abruption placenta

There is no relationship between fasting and abruption placenta. A randomised trial is needed

Thank you all for your valuable comments, I totally agree that we have to do a research to look to the problem in a more scientific & statistical way. 

Regards,

Osaid

estoy de acuerdo con mis antecssores, valdría la pena realizar un trabajo de investigación entre el ayuno y el abruptio placentae, yo trabajo en una clínica en la que se reciben pacientes con estas características

I think no, we need more studies in this regard

I have reviewed lots of literature on this topic but I have not seen this issue studied or talked about.  I think the number of hours fasted would also be an important factor in a study.  Many studies on fasting look at things such as birth weight, bmi, AFI, preterm contractions, etc.  But I seldom see that there is  a certain number hours of fasting related to any adverse outcomes.  So in designing a study, would be nice to see as I think for women that do fast during pregnancy, it would be nice to also know if the number of hours fasted make a difference.  Here in the US most women that fast are unwilling to divulge it to providers although some do.  But overseas in Muslim countries it is a great place.  I would love to do more research in this area insha'Allah.