Maximum DNA synthesis during the midproliferative phase of the cycle (i.e. cycle days 8â10) correlates with the maximum number of mitoses in both the stromal and epithelial endometrial cellular elements, as well as with the midproliferative peak of plasma estradiol and nuclear estradiol receptors.
Some defining characteristics of angiosperms include flowers, carpels, and the presence of endosperm, a nutritive substance found in seeds, produced via a second fertilization event. However, some current studies suggest that endosperm is not unique to angiosperms.
Normal characteristics of the gestational sac include the double decidual sac sign, a continuous hyperechoic rim more than 2mm thick, a spherical or ovoid shape (no angulation) and growth of >1.2 mm/day. Within the gestational sac the yolk sac is the first structure to appear which confirms an intrauterine pregnancy. The yolk sac is seen by transvaginal ultrasound when the mean sac diameter is 5-6mm and should always be seen when the mean sac diameter is greater than or equal to 8mm. The image on the left demonstrates a double echogenic ring which is known as the double decidual sac sign.