gestation period

period /pe·ri·od/ (pēr´e-od) an interval or division of time.

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ejection period  the second phase of ventricular systole, being the interval between the opening and closing of the semilunar valves, during which the blood is discharged into the aortic and pulmonary arteries; it is divided into a p. of rapid ejection followed by a p. of reduced ejection.

gestation period  the duration of pregnancy, in humans being about 266 days (38 weeks) from the time of fertilization until birth. In obstetrics, it is instead considered to begin on the first day of the woman's last normal menstrual period prior to fertilization, thus being about 280 days (40 weeks).

incubation period 

1. the interval of time required for development.

2. the interval between the receipt of infection and the onset of the consequent illness or the first symptoms of the illness.

3. the interval between the entrance into a vector of an infectious agent and the time at which the vector is capable of transmitting the infection.

latency period 

1. latent p.

2. see under stage.

latent period  a seemingly inactive period, as that between exposure to an infection and subsequent illness, or that between the instant of stimulation and the beginning of response.

menstrual period , monthly period the time of menstruation.

pacemaker refractory period  the period immediately following either pacemaker sensing or pacing, during which improper inhibition of the pacemaker by inappropriate signals is prevented by inactivation of pacemaker sensing.

refractory period  the period of depolarization and repolarization of the cell membrane after excitation; during the first portion (absolute refractory p.), the nerve or muscle fiber cannot respond to a second stimulus, whereas during the relative refractory period, it can respond only to a strong stimulus.

safe period  the period during the menstrual cycle when conception is considered least likely to occur; it is approximately the ten days after menstruation begins and the ten days preceding menstruation.

sphygmic period  ejection p.

Wenckebach period  the steadily lengthening P–R interval occurring in successive cardiac cycles in Wenckebach block.

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gestation period

Etymology: L, gestare, to bear; Gk, peri, near, hodos, way

the time span between conception and labor. In humans the period is approximately 38 weeks.

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gestation

the period of development of the young in viviparous animals, from the time of fertilization of the ovum to birth. See also pregnancy.

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gestation period

the duration of pregnancy in the domestic animal species are: cow—273 to 292 days (Bos taurus), 271 to 310 days (Bos indicus); mare—333 to 346 days; ass—365 to 375 days; ewe—143 to 147 days (meat sheep), 147 to 155 days (merino); goat doe—146 to 155 days; sow—111 to 116 days; bitch—58 to 68 days; queen—61 to 70 days.

In laboratory and quasi-pet animals: guinea pig 59-72 days, gerbil 24-26 days, hamster 15.5-16 days, mouse 19-21 days, rat 21-23 days, rabbit 29-35 days.

perpetual gestation chart

a table based on the average gestation period of the particular species, e.g. 63 days for bitches, that plots the anticipated date of parturition against the breeding (conception) date. Designed to be independent of the year so it is valid indefinitely.

prolonged gestation

see prolonged gestation.