Home > Uncategorized > A Matter of Timing

A Matter of Timing

The rate of development at around 12 weeks of pregnancy is amazingly rapid.  The baby’s size doubles and body details develop extremely rapidly within a short span of a few weeks:

“At 16 weeks, the fetus is about 4 and one-half inches long and resembles an infant; the eyes blink, the heartbeat is easier to locate, facial features (nose, mouth, chin and ears) are distinct, and the fingers and toes are clearly developed; the skin on the fingers and toes even have distinct patterns (fingerprints!).”

An error of just 1 week either way has significant implications in depicting what is considered “typical.”  Therefore it is essential to determine with some precision the date of conception, yet the date of conception usually cannot be determined better than within days or perhaps even weeks.  So images that are labeled as a certain age could actually represent an entirely different reality.  For example, there is a distinct possibility that an image labeled as depicting 12 week gestation, could actually be 12 +/- 1 week, or 12 +/- 2 weeks!  Such a mislabeling can produce dramatic errors of understanding due to the rapidity of change at this stage!

Most pregnancy calculations start with the first day of a woman’s menstrual period, and assume a regular 28 day menstrual cycle, but cycles may be irregular and can vary from 21 to 45 days.  The time between the start of the menstrual period and ovulation is calculated as the first 2 weeks of pregnancy based on a 28 day cycle, even though conception has not yet occurred.  However, due to menstrual cycle variations, ovulation and conception could occur within a 1 – 2 week window.  Therefore two women with different monthly cycles but the same start of menstruation could both be pregnant with babies that are as much as 2 weeks apart in terms of actual growth stage and maturity!

Couple that uncertainty with the fact that not all humans develop at exactly the same rate, and we have a conundrum:  Does that “12 week” baby image really depict a “12 week” baby, or is he actually a 10, 11, 13, or 14 week baby?

The difference in maturity is huge.  But we can’t know age for certain at this stage.    That’s why one may see a wide variation in the details among images of babies supposedly at the same stage of development.

In real life it’s not a problem:  The baby will be born whenever it’s ready.  But it could be a problem when we try to define a snapshot “standard” of development arbitrarily at this early stage of life.  So use caution and wisdom.

In truth, whatever we define in our “standard” is immaterial.  What really matters is that the baby is a human being from the moment of conception.  There is no getting around that.  For more details, see post “Baby, Baby.”


Categories: Uncategorized
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  1. May 5, 2020 at 4:30 pm

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