Barbato M, Bitto A, Gray R H, Simpson J L, Queenan J T, Kambic R T, Perez A, Mena P, Pardo F, Stevenson W, Tagliabue G, Jennings V, Li C
Centro Ambrosiano Metodi Naturali CAMEN Milan, Italy.
Adv Contracept. 1997 Jun-Sep;13(2-3):215-28. doi: 10.1023/a:1006508106197.
Various birth defects and untoward perinatal outcomes have been claimed to be associated with pregnancies conceived by gametes aged in vivo before fertilization. Thus, these outcomes were systematically assessed in pregnancies occurring in natural family planning (NFP) users. Our international multicenter cohort study of NFP pregnancies (n = 877) is by far the largest systematic study designed to assess pregnancy outcome and is of sufficient power to allow us to address the concern of low birth weight (< 2500 g) and preterm delivery (< 37 weeks gestation).
In addition to gathering baseline medical data, evaluation was performed at 16 weeks, 32 weeks and at term. Data were collected in a systematic cohort fashion, verified by the five collaborating international recruiting centers, and analyzed by investigators in the US. Most recruiting center principal investigators are obstetrician-gynecologists and, if not, have integral relationships with such specialists. Standard criteria could thus be applied within and among centers. In our cohort, birth weight was recorded accurately at delivery. Almost all of the deliveries occurred in hospitals; thus, data should be quite reliable. Neonatal examination for anomalies was usually conducted immediately after delivery, when birth weight was recorded.
Analysis of risk factors for low birth weight and preterm delivery showed that this population had a low risk profile. Low birth weight infants (< 2500 g) and preterm deliveries were increased among women with a history of either prior low birth weight or preeclampsia in the index pregnancy. However, mean birth weight was unaffected by the timing of conception vis à vis ovulation or pregnancy history. Mean birth weight for the 877 singleton NFP pregnancies was 3349.6 g. The risk of preterm delivery was increased among older women who drank alcohol, but there were no significant effects of timing of conception vis à vis ovulation on preterm delivery. Results held when analysis was stratified according to whether NFP was being used for contraception or to achieve pregnancy.
Our data do not appear to show striking differences between 877 NFP pregnancies and the general obstetric population. The timing of conception vis à vis ovulation does not exert significant effects on the birth weight or preterm delivery of resulting pregnancies, a reassuring finding for NFP users.
各种出生缺陷和不良围产期结局被认为与受精前体内老化配子受孕的妊娠有关。因此，对采用自然计划生育（NFP）的孕妇所发生的这些结局进行了系统评估。我们对NFP妊娠（n = 877）进行的国际多中心队列研究是迄今为止旨在评估妊娠结局的最大规模系统研究，有足够的效力让我们解决低出生体重（<2500克）和早产（<37周妊娠）的问题。
除收集基线医疗数据外，在孕16周、32周和足月时进行评估。数据以系统队列方式收集，由五个合作的国际招募中心核实，并由美国的研究人员进行分析。大多数招募中心的主要研究人员是妇产科医生，若不是，则与这类专家有密切关系。因此，标准标准可在各中心内部和之间应用。在我们的队列中，分娩时准确记录了出生体重。几乎所有分娩都在医院进行；因此，数据应该相当可靠。新生儿异常检查通常在分娩后立即进行，此时记录出生体重。
对低出生体重和早产的危险因素分析表明，该人群的风险较低。在本次妊娠中有低出生体重或先兆子痫病史的女性中，低出生体重儿（<2500克）和早产的发生率有所增加。然而，平均出生体重不受相对于排卵的受孕时间或妊娠史的影响。877例单胎NFP妊娠的平均出生体重为3349.6克。饮酒的老年女性早产风险增加，但相对于排卵的受孕时间对早产没有显著影响。根据NFP是用于避孕还是用于受孕进行分层分析时，结果依然成立。
我们的数据似乎并未显示877例NFP妊娠与普通产科人群之间存在显著差异。相对于排卵的受孕时间对所产生妊娠的出生体重或早产没有显著影响，这对NFP使用者来说是一个令人安心的发现。
