Being married in the Catholic Church is both a challenge and a privilege. Unlike secular marriage, Catholic couples are called to a radical lifestyle of total self-giving to each other; a lifestyle that goes against many of the expectations of our contemporary society which glorifies personal fulfilment and enshrines individuality. These social expectations are especially strong in the sexual arena.
Against this social backdrop, the Church holds out a magnificent vision for marriage. It calls couples to accept sexual intercourse as a sacred body language – a language in which husband and wife express their total, reciprocal self-giving. This total self-giving includes every aspect of a couple’s personhood – their physical, psychological and spiritual realities. It includes their potential to create children.
Natural fertility methods not only make it possible to live this vision of love, they actively nurture a couple’s affection and knowledge of each other as they give of themselves in every act of love. Our lives have been so enriched by the vision of the Church, that it is our earnest desire to share this message with as many couples as possible. We hope that this booklet will dispel some of the myths and encourage every couple who reads it, to give natural fertility methods serious consideration. Byron & Francine Pirola
Under normal circumstances, men are fertile all the time. Sperm are produced continuously by the testes at a rate of around a hundred million per day. The testes begin sperm production at puberty and continue until the man dies, although the number and quality decline with age.
Women are fertile for only one day each cycle, at ovulation; that is, when an ovum (egg) is released from one of her two ovaries. A woman is born with some two million immature ova in her ovaries. Most of these ova never fully mature but gradually disintegrate throughout the woman’s reproductive life. By the time a woman becomes reproductively mature following puberty, approximately 400,000 ova remain in her ovaries. Only 400-500 of these ova will be stimulated to full maturity by the woman’s hormones and about once a month, one will rupture from either the left or right ovary at ovulation. This ovum will live for a mere 12 – 24 hours after which it dies if it has not been fertilised by a sperm cell. The woman continues to release approximately one ovum per month until menopause.
Sperm ejaculated into the vagina will normally die in its acidic environment in a few hours or less. In the days preceding ovulation however, a woman’s cervix (which is at the base of the uterus) produces specialised mucus which can nourish and sustain the sperm for up to five days. This mucus is also important for the filtering of abnormal sperm and the transportation of healthy sperm into the uterus (Fig. 1a). Oestrogen from the ovary causes the cervix to produce specialised mucus (main figure: blue, white) immediately prior to and during ovulation. Healthy sperm swim through this mucus at the cervix into the uterus, while many abnormal sperm are trapped in it.
Of the several hundred million sperm deposited into the vagina during ejaculation, only around 200 will reach the ovum, and only one will be able to fertilise it. Once ovulation has occurred, the specialised mucus is no longer required and the woman’s hormones cause the cervical mucus to change and her resting body temperature to rise about 0.2°C. If the ovum is fertilised, the newly formed embryo begins to develop and will implant in the soft nutritious lining of the woman’s uterus, reaching birth some 8½ months later. If there is no fertilisation, the woman’s uterus sheds the lining it had prepared for an embryo in what is known as menstruation or a ‘period’. After ovulation, the hormone Progesterone stimulates the production of a different mucus (green) that is impenetrable to sperm.
Francine & Byron Pirola are the founders and principal authors of the SmartLoving series. They are passionate about living Catholic marriage to the full and helping couples reach their marital potential. They have been married since 1988 and have five children.
Their articles may be reproduced for non commercial purposes with appropriate acknowledgement and back links.