This guide will assist you in role play as a doctor, nurse, midwife, or similar role, and presents some of the medical elements that are simulated. Users interested in receiving a Physician tag in the Deciduan Users' Group should read and understand the information presented here, then contact one of the group staff to request the tag. Since the male parts are relatively simple compared to the female parts, only the latter will be discussed at length here.
The main difference between the three HUDs (male, female, and "herm") is which genders are available; the "Herm" HUD allows switching between male and female genders, although the female portion is always active. I.e., even if the Herm HUD is in male mode, the female cycle will continue to run. Similarly, the male portions will maintain their own state (e.g., potency). But a Herm HUD user may only couple with another user with the opposite gender active.
The Deciduan female cycle roughly follows the human female menstrual cycle, and is divided into four phases: menstrual, pre-fertile (corresponding to the follicular/proliferative phase), fertile, and post-fertile (luteal/secretory phase). Patients may modify their cycle by changing the duration of the cycle itself (which scales all of the phases equally), or by changing the length of the fertile period (which is always centered within the cycle).
The menstrual phase occupies roughly the first 4-5 days of a normal cycle. It's signified by red hovertext on the female HUD. Additionally, the male HUD can detect this state when coupled -- a red dot will appear within the pink heart.
The pre-fertile phase is somewhat unremarkable, except that for optimal chances of conception, insemination should occur just prior to its conclusion (around day 12 of normal cycle).
The fertile phase is when ovulation can occur. It always occurs once, and may result in more than one ovum being released (see Ovum Release and Fertilization, below). The time of release is somewhat random.
During the post-fertile phase, ovulation will have already occured, but conception may still occur if an ova was released late in the fertile phase. If no ova are fertilized, the cycle will restart with the menstrual phase.
Female cycles lengths will vary slightly, normally lasting 28 days, +/- two days. As such, it is normal for a cycle to extend to day 30 or so.
Ovum Release and Fertilization
Once an ovum is released, it will persist for 1.5 SL "days" (about 9 RL hours with the default settings), and must be fertilized within this period or it will be discarded. Each ovum has a roughly 35% chance of fertilization if sperm was present at the time of ovulation. If insemination occurs after ovulation, then the chances of fertilization are lowered. E.g., if insemination occurs halfway through the ovum's lifetime, then the odds of conception will be reduced by half to about 17%. Each ovum is individually fertilized.
Since Deciduan does not simulate miscarriage or chemical pregnancies, the ovulation rate corresponds to those for human live births, as adjusted by the fertilization factor. With the default settings, there is a one-in-31 chance that two ova will be released, and one-in-6715 chance that three will be released. The patient can, however, determine the ovum release rate. The HUD supplies rates that correspond to several scenarios, such as the effects of the use of clomiphene (Clomid), gonadotropins (IVF drugs), as well as several non-human scenarios.
If a patient has been sexually active with more than one partner, and more than one ova has been released, it is possible for ova to be fertilized by different fathers' sperm. The likelihood that a particular partner's sperm will be responsible for insemination depends on how long ago insemination by that partner occurred, and what that partner's potency was at the time of insemination (it peaks around two SL "days" between ejaculations). Internally, the HUD will track contributions from several partners. There is no advantage to repeated insemination from any given partner. In fact, doing so repeatedly may actually place that partner's sperm at a disadvantage against another partner's due to decreasing potency.
Pregnancy Detection
As in real life, fertilization will not immediately disrupt the cycle. Since cycles vary in length, a patient can not determine whether or not they are pregnant simply by noticing that the cycle has extended beyond 28 days. If conception has occurred, the HUD will continue to remain in a "cycle" state up to day 35 before finally transitioning to the "gravid" state and revealing how far along the patient is. This is meant to give the patient a time to wonder why they are "late," and possibly take a pregnancy test.
After fertilization, each ova will be responsible for its own level of hCG (the hormone for which pregnancy and blood tests are designed to detect). It takes several SL days for the level to rise high enough for detection, though the presence of multiple fertilized ova will decrease this time due to the increased level of the hormone. However, no ovum will produce a detectable level until about six SL days (one RL day) after conception. hCG levels increase on an exponential curve, so the chances of getting a positive test increase dramatically as the expected end-of-cycle approaches. The simple Deciduan Home Pregnancy Tests (HPTs) detect levels of 50 mIU/ml.
A positive HPT will trigger the HUD to switch to the "gravid" state a few moments after the test results are available.
Of course, the Physician's HUD will reveal all elements of gestational state at any time. As such, its use as a role-playing tool should be judicious.
The HUD enters the "gravid" state when one or more ova have been fertilized, and there has either been a positive result from a home pregnancy test or one week has passed since the expected end of the menstrual cycle.
The gestation period is determined at the time the HUD transitions from the "cycle" to the "gravid" phase. For most users, this results in an approximately 280-SL-day cycle, with a 2-SL-week variability (266 to 294 days). If a user changes her day length during gestation, the RL endpoint will move. However, changing the gestation length in the womb settings will only affect the next pregnancy.
During the gestational period, the HUD's main purpose is to act as a timer and to activate attachments (see Changing Shapes). As the pregnancy reaches maturity, the HUD will begin to signal the patient by indicating that Braxton-Hicks contractions are occurring (see Labor and Birth).
Gestation may be interrupted using the Physican's HUD. The 23rd week marks a critical point, when the fetus will be considered viable. Before that time, the Physician's HUD will allow termination. After that, the HUD will allow induction. However, early induction carries some risk of non-viability. Patients can, of course, choose not to role-play this element (it is simply indicated via a message upon delivery).
Labor and Birth
The HUD simulates a labor and birth scene, taking the patients through the three main phases of labor and to delivery. See Labor and Birth to learn about these stages, and the documentation for the The Physician's Kit to learn how to monitor labor and perform delivery.