Maternal Age and Contractility of Human Myometrium in Pregnancy

Abstract

There is controversy as to whether maternal age exerts an influence on the contractility of human myometrium in pregnancy. The aim of this study was to examine a series of functional contractile parameters of human myometrium in vitro, over a broad range of maternal ages. Myometrial tissue specimens were obtained at cesarean delivery from 32 women with maternal ages ranging from 28 to 52 years. Using in vitro recordings, a number of contractile parameters including maximal amplitude, mean contractile force, time to maximal amplitude, maximum rate of rise, and occurrence of simple and complex (biphasic and multiphasic) contractions were examined for spontaneous and induced contractile activity. The relationship between maternal age and individual parameters was evaluated using linear regression analysis. For all contractile parameters examined, for both spontaneous and induced contractions, no significant correlation was observed with maternal age between 28 and 52 years. The mean maximum amplitude values for spontaneous and oxytocin-induced contractions were 23 ± 3 and 43 ± 5 mN, respectively. The mean contractile forces for spontaneous and oxytocin-induced contractions were 1.5 ± 0.2 and 6.5 ± 0.9 mN, respectively. There was no variation in the proportion of biphasic or multiphasic contractions with maternal age. These results indicate there is no significant functional impairment of uterine contractility and no lack in responsiveness of myometrium in vitro, in the older mother. These findings do not support the concept that there may be a biological basis for dysfunctional labor or increased cesarean delivery rates in older parturients.

Spontaneous Human Myometrial Contractility in the Third Trimester of Pregnancy in Relation to Past Mode of Delivery

“…Previous studies from our group have examined a wide range of contractile parameters in relation to maternal age, and no significant difference was found. 13 We are of the view that this difference is unlikely to have had an influence on the results obtained.…”

“…The results from some of the biopsy samples included in this study have previously been reported in different contexts. [11][12][13] Strips of myometrium were excised from the upper lip of the incision in the lower uterine segment as described previously. 11,[13][14][15] The myometrial strips were then placed in physiological salt solution (PSS) at 4°C.…”

“…[11][12][13] Strips of myometrium were excised from the upper lip of the incision in the lower uterine segment as described previously. 11,[13][14][15] The myometrial strips were then placed in physiological salt solution (PSS) at 4°C. The PSS contained the following ingredients: 4.7 mmol/L potassium chloride, 118 mmol/L sodium chloride, 1.2 mmol/L magnesium sulfate, 1.2 mmol/L calcium chloride, 1.2 mmol/L potassium sulfate, 25 mmol/L sodium bicarbonate, and 11 mmol/L glucose (Sigma-Aldrich, Dublin, Ireland).…”

“…Individual contractions were defined as simple, biphasic, or multiphasic, as previously described. 12,13 The percentage of total contractions that were biphasic or multiphasic was described for each strip. The frequency of the contractions was also recorded.…”

The Effect of Maternal Age on Obstetric Interventions in a Low‐Risk Population

“…However, as this and others studies have shown, the association appears to be independent of medical or perinatal complications. Furthermore, despite biologic factors, such as the inefficiency of the ageing myometrium, having been suggested as an explanation, recent evidence in this area does not indicate this to be the case . In addition, Zaki et al, in an analysis of the US Consortiom on Safe Labor data (N = 120,442), found that the progress of first‐stage labor was shorter in older women, regardless of parity, but that the second stage was longer in older, nulliparous women .…”