Eleven women in their first pregnancy were recruited via notice boards at obstetric caregivers, pregnancy keep-fit classes and word-of-mouth. It was an inclusion requirement that they be in their second trimester. They were excluded if they had a history of pelvic surgery or a family history of pelvic floor dysfunction. Questions related to urinary stress incontinence, bowel dysfunction and prolapse were asked and then a detailed history and exam was taken by the chiropractor present.
The subjects were adjusted using high-velocity, low-amplitude adjustments – this was done because previous research has demonstrated that only a high velocity type adjustment can achieve the reflex electromyographic activation desired. The study was only “semi” controlled – a sham intervention of placing the subject into a “set-up” adjustment position without actually applying force to any specific segments or thrusting was used in order to account for any unintended physiological responses, which may come about from mere position placement.
The authors found that in the pregnant group experienced increased levator hiatal area at rest following their adjustment, with an average increase of 2.3cm2. This indicates that the pelvic floor muscles were relaxed at rest. No significant changes were noted in the non-pregnant women.
It was noted that, interestingly, the chiropractic-student control groups’ levator hiatus area during the voluntary Valsalva contraction was 20 ± 4cm2. This is significantly larger than previous “normal” controls and only seen prior to this study in a paper on elite, nulliparous (never given birth) athletes. The levator hiatus area at rest and during maximal voluntary pelvic floor contractions were comparable to previously reported normal measurements.
The authors had two novel observations:
They did not find any differences at resting state between the pregnant women and the control group.
The limitations of the study were discussed. The small sample size and the difference in the time frame between the interventions means that the results of the paper should be interpreted with caution.
Some of the pregnant women had received chiropractic care before, but the vast majority had not. The control group, however, was made up of chiropractic students who have been regularly adjusted for significant periods of time. It is therefore possible that the effects seen in the pregnant group were a function of their first exposure to chiropractic care. That said, the same effects were noted in those members of the pregnancy group who had been adjusted before and this would suggest that those post-adjustment changes were a genuine clinical outcome.
Future research in this area is recommended by the authors to include mothers who both have and have not been adjusted before in order to resolve that particular question. It should also follow mothers through the conclusions of their pregnancies in order to see if the relaxation in pelvic floor muscles changes birth outcomes. It is also worth investigating why it is that chiropractic students could contract their pelvic floor muscles to the degree to which they were capable(1).
The pelvic floor muscles have been demonstrated to be coactivated with the transversus abdominis – which in turn are known to be important in lower back pain(1).
Pregnant women are known to seek chiropractic care for their lower back pain. A survey of South Australian women returned 1531 responses. Of these women, 35.5% of them experienced moderately severe low back pain during their pregnancy and two-thirds of that group reported persistence of that pain after their pregnancy(2). Elsewhere, a survey of pregnant women and their caregivers showed that 61.7% of the pregnant women and 36.6% of their caregivers would support the use of chiropractic care for their low back pain(3). Women who undergo spinal manipulation prior to labour also report less back pain during the delivery(4).
In one report, 75% of pregnant patients who had received chiropractic care during their pregnancy stated they had experienced relief from back pain(5), while another review of records found that there was a rate of relief from back pain among their subjects of 84%. The authors of this work noted that chiropractic care may also decrease the incidence of “back labour”(4) – which is a period of acute, lower-back pain felt during labour that has been treated with injections of sterile water into the paraspinal tissue around the lumbar spine (6).
Women who seek chiropractic care during their first pregnancy have been reported to have, on average, a 25% reduction in labour times while those on subsequent pregnancies have been reported experiencing reductions averaging 31%(7, 8).
In 2017, a case study was published in the Journal of Pediatric, Maternal and Family Health – “Reduction in Placental Insufficiency and Normalized Fetal Growth Rate in a Pregnant Patient Following Chiropractic Care for Vertebral Subluxation: A Case Report”. The report details the care provided to a pregnant mother who had been diagnosed with placental insufficiency and resultant restrictions to foetal growth rate. She was 32 weeks pregnant when she presented for chiropractic care, having previously received her diagnosis of placental insufficiency.
She was adjusted using a combination of Thompson Terminal Point Technique (TTPT) and Diversified manual adjustments. Immediate improvements were noted after her initial adjustment to placental resistance when the patient underwent a routine ultrasound the day after her adjustment. Normalised foetal growth restriction (FGR) was noted on Doppler ultrasound at 36 weeks gestation, 4 weeks after beginning care.
FGR is most commonly caused by placental insufficiency due to inadequate supply of oxygen and nutrients required for the baby to grow. Our understanding of the consequences are still relatively rudimentary but may impact the cardiovascular, metabolic and neurological development of the child into adulthood(9). Lower birth weights have been consistently associated with poorer health outcomes for the child(10).
There is currently no known treatment for placental insufficiency. Methods of caring for the wellbeing of the child through addressing the FGR itself (a consequence of the placental insufficiency) have met with varying levels of success.
Advising a woman to undergo bed rest has been trialled, but no statistically significant difference was found in the weights of the baby at birth or foetal weight.
Dietary supplementation was found to have a small effect, though the weight of the child has been shown to increase by 100-300g. The authors of one study on essential fatty acid supplementation concluded that prenatal DHA supplementation of first-time mothers could result in increased birth sizes in populations where DHA intake was low(11).
Infusion with L-arginine (ARG) was also tried in those women where intrauterine growth restriction was due to increased resistance to uterine blood flow. The authors reported significant decreases in resistance in the women where intrauterine growth restriction was due to elevated resistance levels and concluded that ARG infusion effects uteroplacental circulation in this population(12).
Results of another study showed that ARG supplementation orally improved the biophysical profile, lengthened pregnancy and accelerated foetal gain in women with preeclampsia(13).
This case study represents an early step in an interesting line of future enquiry – with the possibility of offering safe, effective solutions to the previously intractable problem of placental insufficiency.
The care of pregnant women is, for many chiropractors, one of the most rewarding experiences of their practice lives. It would be a valuable addition to the growing body of research surrounding the care of expectant mothers for chiropractors to write up their clinical experiences as case studies in order to further direct future work.
The growth of understanding in the role of pelvic floor muscles in pregnancy and neonatal outcomes are a valuable addition to our understanding of pregnancy care and offer exciting future directions for study. The foundation for the care of women by chiropractors during their pregnancy is ever increasing, while more research is always needed, it can be safely stated that chiropractic can offer a valuable addition to a woman’s pregnancy plan.