GESTATION, GRAVIDITY or PREGNANCY are concepts linked with FERTILITY (impregnable) and FECUNDITY (fertile or capable of delivering "life" - the essence of (femineity) femininity ... FEMALE Femur Family - concepts explored elsewhere).
 
The feminine facet relates to EGG, OVOCYTE as well as with UTERUS, MATRIX, MATERNITY, MOTHER and MOTHERING. Another track relates to ABORTION, MISCARRIAGE, STILLBIRTH and the concept of TERATOTHANASIA given below. The emphasis here is on PREGNANCY and on TERATOTHANASIA (some shorten the term to Terathanasia) to denote the notion of spontaneous death of the embryo-fetus or spontaneous ab-ortion. Nearly 20% of recognized gestations are lost, mostly due to "fatal flaws" of the embryo or fetus. Fecundity rates represents Fertility rates minus Teratothanasia rates. At this point, further elaborations regarding AB ORTION are given separately.
 
The masculine facet relates to SPERM, SEMEN, SEED, SEMINAL and SEMINARY (also explored separately).

GRAVIDITY points to GURU and GRAVis, which in Sanskrit and Latin denote transcendental, significant, weighty, momentous, vital. In this spirit, people conjure GRAVen ideas about GRAVe and GRAVidy. GRAVen ideas are also found among taxpayers as "tax" in Spanish is called GRAVamen and few will dispute that taxes are agGRAVating. In addition, there is little doubt that an IMPREGNAted woman, increasingly feels the impact of GRAVitational forces from growing fetal tissues. In Spanish, GRAVidity is also called emBARazo, as if to point out that pregnant women can be emBARrassed about the social circumstances of their conception or by their growing abdominal dimensions. Furthermore, emBARassed reminds pregnant ladies of BARometic pressure. In Ukrainian "vaha" implies weight as in "grave gravidity" and "vahitna" denotes pregnant, an illustration of the universal links of notions of gravidity with weight.

Historians make reference to IMPREGNABLE fortresses. Poets speak of IMPREGNABLE women. In reality, most women are IMPREGNABLE if fertile and polluted by fertile sperm. Polluted originated as an expression to denote "insemination" or "contamination" or ejaculation of semen. In short, it is not sufficiently appreciated that many IMPREGNABLE fertile women are infertile due to male STERILity which is quite common (over 20% and often due to Y sex CHROMOSOME defects).

Modern science has shown that after conception, the majority of fertilized eggs or ovocytes fail to develop (undetected Teratothanasia is estimated at over 50%). It also has been estimated that Teratothanasia lowers the frequency of malformations at birth by nearly 20%. In other words, if we find the "cure" of Teratothanasia, there will be many more infants with incurable developmental defects. Some scientists proposed that it may be better to find ways to enhance the "natural" ability of the maternal organism to recognize a defective embryo-fetus and initiate the process of Teratothanasia (or "failure to gestate"), thus eliminating the demand for induced abortions, more politely called "interruptions of pregnancies" or wrongly called "medical" abortions (Medicine is not about killing). Consider that "older" women tend to have more infants with Down syndrome and other chromosomal defects. Such "maternal age" effect has suggested to some that as a woman ages, her organism capacity to recognize a defective gestation is diminished and as rates of Teratothanasia decrease, rates of deliveries with fatal chromosomal defects increase ("fatal" because once a child has, for instance, trisomy for chromosome 21, it will manifest Down syndrome and either perish (mortality is much higher than average) or have the fatal fate of being mentally subnormal for life).

In general, a recognized pregnancy has about a 20% chance to end in a spontaneous ABORTION (in popular parlance, a miscarriage). At least 50% of abortions (the term implies spontaneous unless qualified by "induced") are due to fatal embryonic chromosomal defects. Sometimes, the embryo lodges in an ECTOPIC location rather than the MATRIX or uterus. An ectopic embryo may cause potentially fatal maternal hemorrhage.