How many months pregnant?
In Japan the length of pregnancy is said to be 10 months. This is because the Japanese measure pregnancy in terms of lunar months, or rather menstrual cycles, from the date of the last normal period to birth. There are ten missed cycles, so pregnancy is deemed as being ten months (or "monthlies") long.
Westerners on the other hand measure pregnancy in calendar months from the date of conception, which is 9 and a half menstrual cycles, or 38 weeks, or approximately 9 calendar months (depending on the months).
Aparently in Western prenatal clinics too, gestation is measured from the first day of the last menstrual cycle, which is also the first day of menstruation.
What I am not clear about is what marks the beginning of gestation, or the menstrual cycle. Cycles do not have beginnings and ends, since they are circlular.
I guess that one reason is clarity - there is menstrual blood on this day and so the event can be timed and days can be counted. But that seems like an arbitary length of time for both Japanese and Western medics to deem the beginning of gestation.
Is there a medical basis, perhaps in the fact that this is the day that the mother's temperature drops, and stays low until ovulation, or in the level of hormones, the justify the assertion that gestation is medically, 40 weeks long?
Yasuko suggested that the current system, is based upon the transmogrification of the soul: when one egg is thrown out, the soul moves to next egg, so the life of the next egg starts at the death of the previous one.
This may be one cultural explanation. But medically, I am not sure why gestation should be deemed to start at the death and evacuation of the previous egg. Or why the menstrual cycle should be said to "start" at menstruation, instead of at the end of the "previous" mensturation, or at ovulation - the day that the egg leaves the ovum.
One might argue that gestation is the time that the egg is in preparation but, in a sense the egg has been in preparation since the mother was born, or even before that. One could arge that pregnancy is almost infinite!
Upon investigation, measuring gestation from the time of the "last normal period" does seem to be arbitary - based upon a time that can be measured (when conception / ovulation are often more difficult to ascertain).
All the same, I guess that is more natural to say that pregnancy is precisely 10 womens-months since when we are talking about the cycles, periods, time span of a woman's body. If one uses calendar months then there is going to be error in estimating the babies developement depending on the length of the month.
To overcome the miscalculations introduced by the various lengths of Gregorian months, I am told that when Western prenatal clinics characterise the development of the foetus, they also use 4 week months but in order to make pregnancy fit the common conception of 9 months of the Gregorian calendar, the first and last months are considered to be 6 weeks long.
In any event, it seems that the length of pregnancy in Japan is measured in a more natural, female oriented way, from the time of mother's last mensturation in menstrual cycles. Since it is women that do pregnancy, and it is their bodies, this seems like a very sensible way of measuring things.
In the West pregnancy is measured in a more male-oriented fashion, as the number of Gergorian calendar months from the time of conception - when the guy gets involved. Some might argue that the Western system is more child orientated, but there is nothing child orientated about the months of the year. The child is completely unaware of the months of the calendar.
The fact that some Japanese misconcieve the length of pregnancy to be ten calendar months is discussed here. As I mention on that forum, I think that Westerner's characterisation of pregnancy as being nine calendar months involves a misconception too. No pun intended.
Addendum
The Japanese also have a different way of counting age. Children are considered to be one year old at birth, two years old at their first New Years Day, and then they gain a year at each New Year's day, rather than at birthdays. This is influenced perhaps by
1) Less of an emphasis on individualism - hence everyone becomes older on the same day rather than on individual birthdays.
2) The child is considered to have been alive (for 10 calendar months) at birth, so is considered to be one year old (rather than zero years old) at birth. This again may be influenced from view age from the mother's point of view. To a father, a new born baby may be new, and zero years old, but to the mother, the baby is someone with whom she has had almost a year long relationship.
How many months pregnant?
In Japan the length of pregnancy is said to be 10 months. This is because the Japanese measure pregnancy in terms of lunar months, or rather menstrual cycles, from the date of the last normal period to birth. There are ten missed cycles, so pregnancy is deemed as being ten months (or "monthlies") long.
Westerners on the other hand measure pregnancy in calendar months from the date of conception, which is 9 and a half menstrual cycles, or 38 weeks, or approximately 9 calendar months (depending on the months).
Aparently in Western prenatal clinics too, gestation is measured from the first day of the last menstrual cycle, which is also the first day of menstruation.
What I am not clear about is what marks the beginning of gestation, or the menstrual cycle. Cycles do not have beginnings and ends, since they are circlular.
I guess that one reason is clarity - there is menstrual blood on this day and so the event can be timed and days can be counted. But that seems like an arbitary length of time for both Japanese and Western medics to deem the beginning of gestation.
Is there a medical basis, perhaps in the fact that this is the day that the mother's temperature drops, and stays low until ovulation, or in the level of hormones, the justify the assertion that gestation is medically, 40 weeks long?
Yasuko suggested that the current system, is based upon the transmogrification of the soul: when one egg is thrown out, the soul moves to next egg, so the life of the next egg starts at the death of the previous one.
This may be one cultural explanation. But medically, I am not sure why gestation should be deemed to start at the death and evacuation of the previous egg. Or why the menstrual cycle should be said to "start" at menstruation, instead of at the end of the "previous" mensturation, or at ovulation - the day that the egg leaves the ovum.
One might argue that gestation is the time that the egg is in preparation but, in a sense the egg has been in preparation since the mother was born, or even before that. One could arge that pregnancy is almost infinite!
Upon investigation, measuring gestation from the time of the "last normal period" does seem to be arbitary - based upon a time that can be measured (when conception / ovulation are often more difficult to ascertain).
All the same, I guess that is more natural to say that pregnancy is precisely 10 womens-months since when we are talking about the cycles, periods, time span of a woman's body. If one uses calendar months then there is going to be error in estimating the babies developement depending on the length of the month.
To overcome the miscalculations introduced by the various lengths of Gregorian months, I am told that when Western prenatal clinics characterise the development of the foetus, they also use 4 week months but in order to make pregnancy fit the common conception of 9 months of the Gregorian calendar, the first and last months are considered to be 6 weeks long.
In any event, it seems that the length of pregnancy in Japan is measured in a more natural, female oriented way, from the time of mother's last mensturation in menstrual cycles. Since it is women that do pregnancy, and it is their bodies, this seems like a very sensible way of measuring things.
In the West pregnancy is measured in a more male-oriented fashion, as the number of Gergorian calendar months from the time of conception - when the guy gets involved. Some might argue that the Western system is more child orientated, but there is nothing child orientated about the months of the year. The child is completely unaware of the months of the calendar.
The fact that some Japanese misconcieve the length of pregnancy to be ten calendar months is discussed here. As I mention on that forum, I think that Westerner's characterisation of pregnancy as being nine calendar months involves a misconception too. No pun intended.
Addendum
The Japanese also have a different way of counting age. Children are considered to be one year old at birth, two years old at their first New Years Day, and then they gain a year at each New Year's day, rather than at birthdays. This is influenced perhaps by
1) Less of an emphasis on individualism - hence everyone becomes older on the same day rather than on individual birthdays.
2) The child is considered to have been alive (for 10 calendar months) at birth, so is considered to be one year old (rather than zero years old) at birth. This again may be influenced from view age from the mother's point of view. To a father, a new born baby may be new, and zero years old, but to the mother, the baby is someone with whom she has had almost a year long relationship.