Could Silicone Be Safer? Randomized, Prospective Analysis of Complications Associated with Usage of Silicone Nursing Pads Versus Cotton Nursing Pads

Eighty breastfeeding women were studied in their first four months post-partum to assess the frequency of adverse events (mastitis, thrush, duct clogging, nipple injury, and breast milk supply issues) in subjects using traditional cotton absorbent pads and silicone nonabsorbent pads. The subjects were randomized to silicone versus cotton pads and assessed monthly via telephone interview by a blinded reviewer. Cotton pad users were 6.3 times more likely to develop mastitis (p<0.01), 5 times more likely to develop thrush (p<0.05), 11.3 times more likely to develop a clogged duct (p<0.01), and 1.8 times more likely to suffer nipple injury (p<0.05). Inadequate milk flow occurred in both groups and was not statistically significant. Several women using cotton pads complained of excessive milk flow; this problem was not observed in silicone pad subjects. The results imply that silicone pad users may experience a statistically significant reduction in breastfeeding complications, except regarding breast milk supply issues. Introduction: Silicone (non-absorbent) nursing pads (LilyPadz) have been commercially available to breastfeeding mothers since they were introduced to the market in December 2002. They appear to offer some distinct and unique advantages over traditional cotton (absorbent) nursing pads (see discussion). Furthermore, they are designed to prevent breast milk leakage, the safety of which has been questioned but not studied. Finally, they offer a window of opportunity to study whether or not the practice of using absorbent cotton pads should be considered innocuous or that cotton pads may actually unknowingly contribute partially or wholly to complications breastfeeding mothers experience We present the data from the first randomized, prospective single-blinded trial comparing silicone pads to absorbent cotton nursing pads to date. The incidence of nipple injury, mastitis, thrush, duct clogging and breast milk supply issues were reviewed. Methods: After obtaining IRB approval for the study, the Department of Lactation Services began enrolling study subjects. The women were assigned in a random fashion to using LilyPadz exclusively or their choice of absorbent pads. Telephone interviews were conducted monthly with a blinded reviewer for four months following enrollment utilizing a standardized questionnaire. A total of 80 subjects were enrolled. 12 (15%) subjects were excluded for the following reasons; 4 had incorrect contact information, 1 had her phone disconnected, 4 quit breastfeeding before 1 month, 2 never answered and never returned phone calls, and 1 switched pads during the study. 44 out of 80 were followed to four months (55%). The data gathered was evaluated monthly and the incidence of mastitis, thrush, duct clogging, nipple injury or soreness, and breast milk supply issues were quantitatively compared between the two groups and expressed as % per month (see tables below). Results: The number of participants declined every month. We used person-month as unit to estimate incidence of side effects. The observed person-months were 144 for silicone nursing pads users and 115 for traditional nursing pads users. The null hypothesis is the side effects incidence in silicone nursing pads users is not different from in traditional nursing pads users. The Poisson model (Breslow and Day, 1987) is used to test the hypothesis: Pr (d=x) = exp (λn)( λn)/x! Where λ denotes the mean of incidence rate in traditional nursing pads users, n is the person-months denominator, and x is the number of incidence cases in silicone nursing pads users. We summed up the probability of incidence cases occurring in silicone nursing pads users under null hypothesis assumption and the probability of more extreme number of incidence cases. The summation of these probabilities is presented below. Breslow NE and Day NE. Fitting Models to Grouped Data. In: Breslow NE and Day NE. Statistical Methods in Cancer Research. World Health Organization, International Agency for Research on Cancer. Lyon, 1987 page119-176 32 subjects were randomized to use traditional nursing pads and 48 subjects were randomized to use silicone pads (LilyPadz). 12 were excluded as for the reasons mentioned above. The remainder of subjects followed per month is shown in Table 1. Table 1. Number of Patients