Presence of Group B Streptococcus in Raw and Dehydrated Placentas

Research Questions

This experiment set out to answer 2 questions. (1) Is GBS present in the raw placenta of mothers who had positive test results for GBS during pregnancy? (2) If GBS is present in the raw placenta, is the process of encapsulation sufficient to inhibit the survival of GBS in the dehydrated placenta?

GBS screening is now routinely performed on all pregnant women during their 35th–37th week of pregnancy,¹⁴ and the universal administration of prophylactic antibiotics during labor for women who have positive test results for GBS has decreased the incidence of neonatal GBS infection by 80%.^15,16 Therefore, it is hypothesized that the placentas will have negative test results for GBS at birth. It is further hypothesized that in placentas contaminated with GBS, the process of dehydration will significantly reduce the survival of GBS.

Placenta Donation and Collection

This study was approved by the Internal Review Board (IRB) and Biosafety Committee of Augusta University (Appendix 1). Verbal consent was obtained from each mother to use her placenta in adherence with IRB requirements (Appendix 2). All placentas came from the Atlanta Birth Center or an Atlanta area hospital. Twelve placentas were collected from postpartum mothers who had positive test results for GBS via a vaginal swab during pregnancy and had a vaginal birth. Exclusion criteria included mothers who have a condition that requires medical intervention during pregnancy, mothers with an active infection at the time of birth, and mothers delivering by cesarean section.

Preparation and Encapsulation

There are 2 common methods of placenta encapsulation used today. One method involves steaming and dehydrating the placenta (steamed-dehydrated method), while the other excludes the steaming step and involves just dehydration (raw-dehydration method). The raw-dehydration method was chosen over the steamed-dehydration method because previous studies have shown the steamed-dehydration method to destroy more microorganisms than raw dehydration, and it was advantageous to test the method that would pose the greatest risk.¹ Therefore, by extrapolation, it can be assumed that steamed-dehydrated placentas would show an even greater reduction in the presence of GBS.

The individual placentas were either frozen or processed within 48 hours of collection. Each placenta was stored and processed separately. Placentas were thoroughly rinsed, and blood clots were removed. The amnion, amniotic sac, and umbilical cord were removed and discarded. The placenta was sliced into thin strips using stainless steel scissors and placed on parchment paper on trays of a Nesco Snackmaster Pro dehydrator. The strips were thoroughly dried for 18–24 hours set at 160°F, measured by the dehydrator thermostat. After drying, the placenta strips were tested for dryness by snapping them in half. If they did not easily “snap,” they were dehydrated further.¹ The dried strips were ground into a fine powder using an Oster blender. The placenta powder was the final product. In commercial encapsulation, this dried powder is then put into gelatin capsules for oral administration. All surfaces and equipment were cleaned and sanitized using a 10% bleach solution for 10–30 minutes between each sample preparation, according to Occupational Safety and Health Administration standards for sanitation for bloodborne pathogens.¹⁷

Testing for GBS

Before processing, both the maternal and fetal sides of the placenta were swabbed with a sterile cotton swab and the swab was immediately placed in a Hardy Diagnostics Strep B Carrot Broth to detect the presence of GBS in the raw placentas.^18⇓-20 The Carrot Broth was incubated at 37°C for 24 hours and read the following day for a positive or negative result. An orange color indicated the sample was positive for GBS, while no color change indicated a negative result.²¹ For further confirmation, a Hardy Diagnostics GBS Detect plate was then streaked with a loop of the Carrot Broth sample. The GBS Detect plates were incubated for 24 hours at 37°C and read the following day for growth or no growth.²² Both media are selective for GBS. A quality control (QC) was run alongside each batch of samples, using a pure culture of commercial GBS grown on sheep blood agar.

Most of the placentas initially had negative test results for GBS. To test the second research question of whether the encapsulation process is sufficient to kill GBS, individual samples of placenta were manually contaminated with GBS. The placentas were split into 55 individual samples and processed each sample as a separate specimen. Using a 0.5 McFarland standard made from the QC-GBS culture, 1 to 4 drops of GBS was used to contaminate 46 of the 55 placenta samples. Each placenta sample was then retested using Carrot Broth and GBS Detect plates, as previously described, to ensure each sample had been successfully infected with the GBS. Each sample was then dehydrated and processed individually according to the encapsulation method described in the previous section. After the placenta sample was fully dehydrated and ground into powder form, the dried powder was swabbed and tested using the same procedure as the previously described raw samples.

Statistical Analysis

For each placenta sample, the results were recorded of the raw-unadulterated placentas, the contaminated samples, and the dehydrated-placenta powder as positive results for GBS or negative results for GBS. Relative risk (RR), relative risk reduction (RRR), and absolute risk reduction (ARR) analyses were used to determine if the process of encapsulation reduced the amount of GBS present.²³ The RR in this case is the ratio of the probability of the dehydrated placentas having GBS vs. the probability of the raw contaminated placentas having GBS. The RRR is the ratio of the probability of the dehydration process reducing the presence of GBS compared to the raw contaminated placentas.

Interpretation of Results

Only 2 of the 12 original placentas initially had positive test results for GBS, indicating that a low percentage of placentas are colonized with GBS even from mothers who had positive GBS test results during pregnancy. The encapsulation process of dehydrating the placentas reduces the GBS present on the placentas an additional 69.6%. When the 2 research questions are considered together, there is approximately a 5.1% chance that a placenta from a mother who had a positive test result for GBS during pregnancy will have a positive test result for GBS after the encapsulation process.

Research Findings

It was hypothesized that no placentas would have positive test results for GBS after birth because of the universal administration of prophylactic antibiotics given during labor.^14⇓-16 It was found that a low percentage of placentas had GBS-positive test results after birth, but not all had GBS-negative results. However, the 83.3% negative results correlate with the 80% reduction in newborn-GBS infections seen in previous studies since the implementation of universal antibiotics.¹⁵ Furthermore, it could not be confirmed that all mothers who donated their placentas had received prophylactic antibiotics during labor, which could account for the 2 positive results. The only other placenta study that has performed a microbiological analysis of placentas found all raw placentas in their study to have negative results for GBS.¹

For the manually infected placentas, the ARR of 69.57% with P < 0.0001 represents a statistically significant decrease in risk. This suggests that the dehydration process significantly reduces the survival of GBS on placentas that were infected in the raw state, which supports this study’s second hypothesis. Similarly, the microbiological study by Johnson et al¹ showed a significant decrease in microorganisms after dehydration.

This study was limited by the relatively small sample size of placentas and the unknown status of whether the mothers received antibiotics during labor. In contrast, the samples that were manually contaminated most likely had a greater amount of GBS on them than naturally colonized placentas, which could cause the number of placentas with positive test results for GBS after dehydration in this study to be falsely elevated. Active infection of the mother or baby at the time of birth is a contraindication of placenta encapsulation, so placentas with an infectious dose of GBS would not traditionally be consumed.¹

The findings of this study are important because they provide empirical data rather than speculation about the risk of placentophagy to the mothers with GBS-positive test results and their newborns. Many physicians have been using a single case study to discourage mothers from encapsulating their placentas, even if the mother does not have a positive GBS test result.^4,11 A single incident may warrant further research but does not provide sufficient data to make sweeping recommendations to an entire community. This is especially true when larger studies show no adverse neonatal outcomes in women who encapsulated their placentas.⁵ While the CDC case study of the newborn infected with GBS found GBS in the placenta capsules, the physicians could not rule out other modes of transmission, such as direct contact with family members who might be colonized with GBS or that the antibiotics may not have eradicated the initial infection and could not establish a route of infection from the placenta capsules to the newborn.¹¹ This study provides the much-needed follow-up data that allow physicians and new mothers to know the statistical risk of their placentas containing GBS after birth and after the encapsulation process.