Exploring menstrual products: A systematic review and meta-analysis of reusable menstrual pads for public health internationally

BACKGROUND

Girls and women need effective, safe, and affordable menstrual products. Single-use menstrual pads and tampons are regularly provided by agencies among resource-poor populations. Reusable menstrual pads (RMPs: fabric layers sewn together by an enterprise for manufacture of menstrual products) may be an effective alternative.

METHODS

For this review (PROSPERO CRD42020179545) we searched databases (inception to November 1, 2020) for quantitative and qualitative studies that reported on leakage, acceptability, or safety of RMPs. Findings were summarised or combined using forest plots (random-effects meta-analysis). Potential costs and environmental savings associated with RMPs were estimated.

RESULTS

A total of 44 studies were eligible (~14,800 participants). Most were conducted in low- and middle-income countries (LMIC, 78%), and 20% in refugee settings. The overall quality of studies was low. RMP uptake in cohort studies ranged from 22-100% (12 studies). One Ugandan trial among schoolgirls found leakage with RMPs was lower (44.4%, n = 72) compared to cloths (78%, n = 111, p<0.001). Self-reported skin-irritation was 23.8% after 3 months among RMP-users in a Ugandan cohort in a refugee setting (n = 267), compared to 72.8% at baseline with disposable pad use. There were no objective reports on infection. Challenges with washing and changing RMP were reported in LMIC studies, due to lack of water, privacy, soap, buckets, and sanitation/drying facilities. Among 69 brands, the average price for an RMP was $8.95 (standard deviation [sd] $5.08; LMIC $2.06, n = 10, high-income countries [HIC] $10.11), with a mean estimated lifetime of 4.3 years (sd 2.3; LMIC 2.9, n = 11; HIC 4.9 years, n = 23). In 5-year cost-estimates, in LMICs, 4-25 RMPs per period would be cheaper (170-417 US$) than 9-25 single-use pads, with waste-savings of ~600-1600 single-use pads. In HICs, 4-25 RMPs would be cheaper (33-245 US$) compared to 20 single-use tampons per period, with waste-savings of ~1300 tampons.

CONCLUSION

RMPs are used internationally and are an effective, safe, cheaper, and environmentally friendly option for menstrual product provision by programmes. Good quality studies in this field are needed.

Experimental study of blood lead kinetics in estuarine crocodiles (Crocodylus porosus) exposed to ingested lead shot

A previous study of lead (Pb) contamination in estuarine crocodiles (Crocodylus porosus) in Kakadu National Park, Australia, found elevated Pb levels in bone and flesh from individuals caught in habitats where hunting with lead ammunition had occurred. Lead shot was suspected as the potential source of Pb in these animals. An investigation was designed to determine if crocodiles are capable of retaining and dissolving lead shot in their stomachs and absorbing the ionic Pb into the blood. Four of the six juvenile crocodiles (C. porosus) used in the experiment were fed an initial dose of five or ten lead shot each. Most of the lead shot were retained in the stomach over the 20-week experimental period, as confirmed by stomach lavage and radiography of the stomach region. From 13 to 30% of the original weight of individual lead shot had been eroded in that time. In vitro experiments confirmed that lead shot could be dissolved under conditions simulating those known for the crocodilian stomach. Blood Pb concentrations increased by an order of magnitude within a week after dosing three crocodiles with five lead shot each, and then attained steady-state equilibrium 5-20 weeks after dosing, with blood Pb steady-state levels ranging from 278 to 363 microg/dL. The blood Pb concentration-time curves in these crocodiles followed a one-compartment model with first-order loss kinetics that yielded an apparent biological half-life for Pb in blood of about 3.4 days. Throughout the experiment, the crocodiles remained in apparent good physical condition and displayed no clinical signs of Pb toxicosis. These observations, together with the very high blood Pb levels that were sustained for several months, suggest that crocodilians may possess a relatively high degree of resistance to Pb toxicity.

Association between surface electromyography of human jaw-closing muscle and quantified food breakdown

Simultaneous recordings of the activity of the masseter and anterior temporalis and of jaw movement were made on 10 healthy dentate volunteers while they chewed roasted peanuts in their habitual manner. The quantity of food taken was altered by varying (a) its total weight (mouthful) between 8 and 1 g, but with a fixed initial particle size and (b) by varying its initial particle size between median sizes of 9.2 and 2.4 mm, but keeping the mouthful constant. Significant differences were found in the peak and mean (r.m.s.) estimates of muscle activity (particularly in the masseter), and the dimensions of jaw movements. These differences were associated with the variation in both the size of the mouthful and of the initial particles but were much greater with changes in the mouthful. A dimensional argument treating both the weight of food in the mouth and initial particle size as volumes showed that initial particle volume had been varied by approximately 50 times as much as mouthful volume and therefore that the mouthful was a far more critical factor in masticatory physiology than was the particle size of the food. The reasons for this probably lie in an understanding of mechanisms of food comminution.