Which of the following is an indicator of a healthy early pregnancy?

The presence of a thickened endometrium is a strong indicator of a healthy early pregnancy. During the early stages of pregnancy, hormonal changes, particularly due to the influence of progesterone, lead to the proliferation of the endometrial lining. A thickened endometrium suggests that the uterine lining is adequately prepared to support the developing embryo, which is crucial for a healthy pregnancy.

When evaluating early pregnancy via ultrasound, a thickened endometrium reflects the uterine changes necessary for implantation and subsequent growth of the embryo. This is an important sign that the body is responding appropriately to the pregnancy hormones and is creating an optimal environment for fetal development.

In contrast, other options do not signify a healthy early pregnancy. For instance, the presence of fluid-filled cysts, while often seen in the ovaries during early pregnancy, does not specifically indicate a healthy pregnancy but rather can be seen in various conditions. The absence of a gestational sac at a certain point in gestation would typically raise concerns about the viability of the pregnancy. Similarly, placental previa, where the placenta improperly implants in the lower region of the uterus, can lead to complications and is not an indicator of a healthy early pregnancy.