Fertility and the Moon

Moon phases

The Moon controls the tides and rules over the biological rhythms of plant, animal, and human life. Her monthly cycle is the archetype of all cycles in life. As the mother figure in astrology, she governs the menstruation cycle, breasts, stomach, and childbirth. For the 'modern' western mind, the subject of the moon influencing reproductive lives can sound esoteric, far-fetched, or generally outlandish, but there's ample ancient lore, anecdotal evidence, and scientific studies that seem to prove fertility and the moon are connected in some mysterious way.

The Jonas Method

Pregnant Couple

In the 1950s, Dr. Eugen Jonas, a Czechoslovakian physician, stumbled across an ancient Assyrian astrological text stating "women are fertile during certain phases of the moon." These few words from an ancient text prompted him find out exactly which phase of the moon it referred to. After a lengthy period of research and endless calculations, he found his answer.

Briefly, Dr. Jonas found that in addition to the standard period of ovulation, calculated two weeks following the last menstrual cycle, women can also conceive when the sun and moon duplicate the angle they were sitting at the moment the woman was born. He called this a time of "spontaneous ovulation" and found conception occurred with greater frequency during this Sun/Moon relationship than during the standard ovulation cycle.

Interestingly, it doesn't matter which stage of her cycle a woman is in. When the moment is right, it's right. Spontaneous ovulation occurs and the probability of conception is very high, even if it coincides with the woman's menstruation.

Dr. Jonas put his finding into practice in the mid-1960s and was able to help women use their personal Sun/Moon angular relationship not only as a natural form of birth control, but also to help seemingly infertile women become pregnant. The Jonas Method is still in use today as a means of natural birth control and by many anxious parents who were once seemingly unable to conceive.

The Jonas Method is outlined in detail in the book Astrological Birth Control, by Sheila Ostrander and Lynn Schroeder.

Once in a Blue Moon

One might think that a blue full moon could be a 'once in a blue moon' chance to get pregnant. But a blue moon is actually just a full moon that doesn't quite fit in with the months in the calendar. One version of the blue moon story says that since each of the 12 full moons of a normal year had been given a name, for instance, September's Harvest Full Moon, that the 13th full moon in a year also needed a name. So the extra full moon was named blue.

The Lunar Phases and a Woman's Monthly Cycle

Over the years, scientists have set out to see if there was any true link between a woman's monthly cycle and the moon's monthly cycle. What did they find?

  • Studies in 1980 and 1986 both found a woman's menstrual cycle is in sync with the moon's phases. However, the 1980 study found women were more likely to ovulate during the dark of the moon, while the 1986 study found women were more likely to menstruate during the dark of the moon.
  • In 2014, a somewhat unique and technology-enabled study of more than 8,000 women was presented by infertility specialist Philip Chenette M.D. at the 2014 American Society for Reproductive Medicine's annual conference in Honolulu. This study also found a link between the timing of a woman's monthly cycles and the phases of the moon. This research, like in 1980, indicated that women are more likely to ovulate during the dark of the moon.
  • Just to confuse things a bit more, in 2013 a long-term study of 74 women with 980 menstrual cycles over a calendar year found no synchrony between the lunar phases and the menstrual cycle.

One thing that can be deduced from most of these studies is that the researchers found it is most often the full moon and the new moon phases that are synced in some way with a woman's menstrual cycle and fertility. All the other phases seem to be of little importance.

Perhaps these various studies produced such contradictory and confusing findings because the researchers were looking for synchrony between each woman's personal menstrual cycle and the collective lunar cycle, when they should have been using the personal lunar cycle of each woman. The personal lunar cycle is based on the return of a person's natal Sun/Moon angular relationship.

Astrological Signs and Fertility


While it's very important to know the moment of maximum fertility, the astrological signs seem of little importance in determining this. However, if there's concern about fertility itself, this can be determined, though not definitively, by analyzing the natal chart for fertility. Fertility astrology uses traditional techniques that have been in use since at least the 1st century B.C.

Traditional astrologers classify the signs as fruitful, semi-fruitful, and barren.

  • Fruitful (fertile) signs are: Cancer, Scorpio, Pisces
  • Semi-fruitful (semi-fertile) signs are: Libra, Taurus, Capricorn
  • Barren signs are: Aries, Gemini, Leo, Virgo, Sagittarius, Aquarius

The planets also have their own division in fruitful, semi-fruitful and barren classifications.

  • Fruitful (fertile) planets are: Moon, Venus, Jupiter
  • Semi-fruitful (semi-fertile) planets are: Mercury
  • Barren planets are: Sun, Mars, Saturn

When analyzing a natal chart for fertility, fruitful planets in fruitful signs indicate fertility. Barren planets in barren signs indicate infertility. There can also be fruitful planets in barren signs and vice versa. If the indicators look equally balanced, no determination can be made.

Additionally, whether a couple will have children can't be judged from the woman's individual natal chart with any degree of accuracy because having children is not dependent on the woman only. The natal charts of both prospective parents must be compared, and the individual indications blended to determine the overall fertility potential. Further, any of this can be modified by transits or progressions that can either amplify or lessen the potential.

So take these classifications with a grain of salt because they only scratch the surface. Astrological prediction of fertility is a vast and complex topic that's best handled by an astrologer whose specialty is fertility astrology.

Family Planning the Natural Way

New born baby

Perhaps it's an accident of nature or just pure coincidence that the moon takes 29.5 days to revolve around the earth, and that's about the same length of time most women have in their menstrual cycle. Even scientists seem to agree it's not unreasonable to consider the moon has something to do with fertility. So, for couples seeking a more natural way of family planning, getting in tune with the moon and her cycles could be the best natural birth control and fertility treatment available.

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Fertility and the Moon